Now I have the BIP38 public and private keys. So I print these.
Let's call them Bitcoin address and BIP38 encrypted private key. The address isn't encrypted.
In order to validate this wallet is functioning correctly, I use bitaddress.org's "wallet info" tab and enter the encrypted (6P...) private key on my paper wallet and passphrase.
All good so far!
Success. It opens a bunch of different addresses; the important ones I'm guessing are "Bitcoin Address" and "Bitcoin Address Compressed"
I suggest to only use the Compressed address, which is what bitaddress.org uses by default.
Also, "Private Key WIF 51 characters base58, starts with a '5'" and "Private Key WIF Compressed 52 characters base58, starts with a 'K' or 'L'".
You'll only need the Private Key WIF Compressed to use your funds from the compressed address.
I was under the impression that the "Bitcoin Address" was supposed to match the public key on my physical paper wallet, which goes along with the "Private Key WIF 51 characters base58, starts with a '5'".
However, I notice my physical paper wallets public address does not match the displayed "Bitcoin Address" from the "wallet info" tab. Instead the "Bitcoin Address Compressed" matches.
By default, it uses the compressed address. This reduces fees when you make a transaction.
So if I were importing and sweeping this wallet onto a hot wallet, would I use the "Encrypted Private Key (6p...)" as seen on my physical paper wallet
If your wallet supports it (my phone wallet Mycelium does), you can import/sweep the BIP38 encrypted key directly and enter the password in your wallet.
or the "Private Key WIF 51 characters base58, starts with a '5'" or "Private Key WIF Compressed 52 characters base58, starts with a 'K' or 'L displayed in the "wallet info" tab?
This works too. Decrypting the BIP38 private key before importing/sweeping works in almost any wallet.
Furthermore, is opening the wallet under "wallet details" on bitaddress.org (offline) using the encrypted private key on my paper wallet and passphrase, and seeing the matching "Bitcoin Address Compressed" to the physical paperwallet's public key in my hand, enough to verify the wallet is functioning correct and to begin sending funds to?
This is what I do too.
You could be even safer by using other software to decrypt the private key, so you don't rely on bitaddress only. I've used bitcoinpaperwallet.com for this, although I think it uses the same engine.
Before funding your paper wallet with high amounts, I suggest to make a small transaction first, and sweep it into a wallet to experience how it works. Fees aren't that high at the moment.
After this transaction your paper wallet can no longer be called "cold storage": create a new one.
