Exactly! Bitcoin uses the UTXOs model. Each transaction consists of Inputs and Outputs and an Inputs is basically the output of a previous transaction.
The balance of an address is the sum of all its UTXOs (unspent transaction outputs) or simply the outputs it received from previous transactions but didn't spent them yet.
Now, if you want to create a transaction, you will use as much as needed of UTXOs to cover the spent amount and network fees. However you should know that an unspent transaction output has to be spent in full. So, if the value of the used inputs is bigger than the amount you want to spend (plus fees), the difference will be sent to one of your wallet addresses as an extra output.
Almost all bitcoin wallets do this automatically, though.

@OP, do you get the same error when you use Binance app? What about when you try to withdraw all your BNB tokens, do you get 2.4 or only 0.01bnb?
Not sure but it looks like the famous "Insufficient balance" bug which was supposed to be fixed a long time ago!
That bug is temporary and you should be able to exchange your tokens by now. If the problem persists, try to open an order and cancel it before it gets filled and see if it solves the problem.
If nothing works, you'll have to contact the customer support to look into it.

It wasn't Tron, it was Faceter ICO.
I'm pretty much sure it was Faceter because:
Firstly, They conducted their pre-sale in February 2018 wich coincides with the date on which you made the transaction: Feb-09-2018
Secondly, Faceter price during the pre-sale was 0.0000872 eth and you sent 0.2799 eth. 0.2799/0.0000872=3209 which is almost the same number of FACE tokens you have on your address.

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Sorry for that. I was just answering your question regarding which token you bought.

The feerate suggested by mempool space for a high priority transaction has dropped from ~40 sat/vb to ~25 sat/vb just in the last hour and the number of unconfirmed transactions is decreasing. I would just wait if I were you.
Since the transaction can't be replaced and you don't own the receiving address' private key, there isn't much you can do from your end other than using a paid transaction accelerator (viabtc) or contacting the exchange's customer support and see if they are willing to help.

اعتقد ان كل ما في الامر هو مجرد سوء تفاهم.
من الواضح ان ما قصده الاخ coupable هو ان مواقع الصنابير التي يتم الاشهار لها هي غير مفيدة و اغلبها لا تقوم بالدفع و الاحتيال على العملاء و لم يقل ان الموقع نفسه يمكن ان يتحيل. هو دعى الى عدم تضييع الوقت على مواقع الصنابير و اعتقد اننا كلنا نتفق معه في هذا الموضوع.

لكن كصاحب موقع يجب التثبت من صدقية كل الاعلانات و المواقع التي تشهر لها في موقعك و النقاش لا يفسد للود قضية 

لا يوجد اي تحديث لحد الان بخصوص هذا الموضوع ليس من المؤكد بعد ما اذا كانت جنرال موتورز ستبدا بقبول البيتكوين رغم ان الاستبيان الذي قاموا به لمعرفة راي عملائهم بخصوص هذا الموضوع تم منذ فترة و من المفترض ان يكونوا قد اتخذوا قرارهم بهذا الوقت.

قرات المقال من جديد و ما لفت انتباهي هو تعليق المدير التنفيذي للشركة حول عدم اعتزامهم الاستثمار في البيتكوين على عكس شركة تيسلا. هم فقط يدرسون امكانية اضافة البيتكوين كوسيلة دفع.

البعض يعتقد ان الانتقال ل eth2 لن يحدقث ابدا او على الاقل لن يحدث في القريب و سيبقى فيتاليك يؤجل الانتقال في كل مرة لسبب مختلف.
شبكة اثريوم اصبحت موضوع تندر بسبب مركزيتها اذ ان شخص واحد و هو فيتاليك يتحكم فيها بشكل كلي و تقريبا كل المطورين غادروا للعمل على مشاريع اخرى و لم يبقى الا هو.
المعدنون من مصلحتهم ان لا يتم التحويل و يتواصل التاخير لكن لست متاكد من مدى قدرتهم على فرض رايهم على عكس الشبكات اللامركزية فعليا مثل البيتكوين.

^^
أغلب الشركات العالمية و خاصة التي تشتغل في المجال التقني لا تهتم كثيرا بالشهادة العلمية للمترشحين بقدر ما تهتم بخبرتهم في المجال الذي سيتم توظيفهم فيه لذلك تجد أن الشركة تطلب من المترشحين تقديم نماذج من المشاريع التي اشتغلوا عليها في السابق او رابط حسابهم على GitHub قبل شهادتهم الدراسية.

طبعا التكوين الاكاديمي مهم لكنه لم يعد المعيار الرئيسي لتحديد المترشح الافضل. الق نظرة على العروض في ذلك الرابط و لن تجد اي شرط متعلق بالمستوى الدراسي.

OP's problem is not whether his addresses are segwit or legacy. His problem is that he is importing invalid private keys or he's exported them from Armory in a format that Electrum does not accept. This is why the Next button is not clickable.
@OP, when you exported the private keys, did you check the "Private Key (Plain Base58)" box? Do the private keys start with "L" or "K"?

This is in fact the main disadvantage of symmetric encryption. Sharing the key with the receiver is very challenging as there is a risk a malicious party might intercept it and use it to decrypt the exchanged messages. Asymmetric encryption solves this problem by using a key pair where the public key can be shared publicly while the private key have to be kept secret.
OP, if you have the time, I'll appreciate if you focus more on the pros and cons of each of these encryption types and give some examples and real life applications as this is a very interesting subject.

Unfortunately, no!
By recovering the wallet using only the 24 words seed you will get the same dummy wallet you already have on your HW.
Many confuses the Ledger passphrase with the password other wallets use. The password you define when you create a wallet, for example, with Electrum, only serves to encrypt the wallet file on your device. Therefore, even if you lose it, it is still possible to recover your wallet if you have its seed. The passphrase on the other hand is part of the seed itself and losing it is the same as losing the whole seed.
Your friends only option right now is to try to brute force it.

The problem here is that you didn't hit the "send" button right after you adjusted the fees.
The only way for this to happen is if you adjust the fee rate to something lower, obviously, then you close the "confirm transaction" window and adjust something in the transaction preferences. By doing this, Electrum will act as if you are going to create a new transaction. Hence why the max button become clickable again. It's annoying but it makes sense.

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BC do not support segwit addreses.

If the Next button remain grayed out it means you didn't enter a valid private key.
When you exported your wallet private keys from Armory, did you follow the steps as per HCP's guide linked above? Specifically this part:

Also, make sure to enter only one private key per line and that there are no white spaces at the beginning or the end of each line.

You only need to use the file or qrcode buttons when you have exported your keys in those formats.

The smallest unit in bitcoin is Satoshi and if the need to add more decimals arises then we will be simply creating a smaller unit but this doesn't make the bitcoin supply infinite.
Take the lightning network as an example. It allows sending fractions of Satoshis but this does not change the total supply of bitcoins.

If we want the supply to become infinite then we should remove the block reward halving rule as it's it what ensures we can't mine more than 21 million btc.

As long as we don't know for sure how those exchanges and chain analysis companies working with them track transactions and based on what the flag addresses as suspicious, we can't tell how much "ricochet" is going to be effective.
In fact, it can even be counterproductive as it may raise suspicions if the ricochet transactions have been made in a short span of time.
However, I doubt exchanges will suspend all accounts that can be linked to tainted coins unless the deposited amount is really big or one of its addresses is directly involved in illegal activities.

Is it possible you added an extra word to the seed when you created your wallet the first time! Because I can't think of any other reason why you can't recover it. It's supposed to be a straightforward process.
The 25th word (aka passphrase) is totally different from the password. It's part of the seed and if you add it you will get a different wallet with different addresses.
Probably this is why you don't see your addresses when you recover your wallet with only 24 words (which is the main purpose of using a passphrase).

dkbit98 raised a good point. Anyone who is going to use AirGap wallet is likely going to use an old mobile with an old Android version especially the mobile for the AirGap Vault. And since it is going to be an arirgapped device it would be better if you makeAirGap Vault compatible with old versions than asking the user to upgrade his device which require an Internet connection.
Also, in this guide on how to create a wallet: https://medium.com/airgap-it/airgap-the-step-by-step-guide-bff36d50a4ed it sais you have yo "Use your fingerprint to store the secret in the secure enclave of the mobile device"! is this mandatory? If yes then what about devices that are not equipped with fingerprint sensors?

You should never store your coins on exchanges or any other custodial services because there is always a risk to lose them regardless of how trusted that service is.

As suggested above, hardware wallets like Ledger and Trezor are a good choice. They are secure, easy to use and support different cryptocurrencies but if you can't afford to buy one then there are other good and free alternatives. Personally, I would suggest Electrum (download it from the official website: electrum.org). I've been using it on mobile and desktop for years and didn't lose a single satoshi.
Using a good and reputable wallet isn't enough to keep your funds safe, what you also need to learn is how to secure your wallet and back it up properly.

The biggest problem with bitcoin, imo, is scalability. Most of the cons mentioned above are in one way or another caused by the inability to process a big number of transactions in a reasonable period of time. 

The network can process only ~4.6 tansactions per second which is a very small number compared to other payment methods.
It's mainly due to the small size of blocks and the time it takes to find one. Although some solutions have been introduced to solve this problem (LN, Segwit, Taproot...), the network still get congested from time to time.

This is not true and it's a common misconception.
Miners do not perform complex calculations or solve complex mathematical problems as you would read on most crypto related websites.
Miners simply compute the hash of the block header twice: (sha256(sha256(block header))) and they keep doing this till they find a winning hash.
What makes mining hard and time/power consuming is the difficulty which is adjusted according to the network hashing power.
Miners or at least most of them do not use computers (CPUs) to mine anymore, they rather use GPUs or ASICs.