If all you have to invest is .5 ether I would be careful putting it into ICO's. There are still great ICO's out there but the days of short term 5-10x gains on many ICO's are mostly gone. You'd likely be better off putting your ether into a couple projects that have been around for a while and have shown their teams are trustworthy and consistently working/improving their coins/tokens. Do your own research but personally I think VeChain/ICON/Walton are very safe bets that have a lot of room to grow in the medium to long term.

 If you are looking for a more risky investment that could pay off huge look into COSS. It's a crypto exchange that pays 50% of its fees to token holders and will be opening a fiat gateway in march(hopefully, we'll see if they pull it off). As of now your ROI with their current trading volume is a little less than 1% a year, however if they reach the top 10 in daily volume traded (~270million daily), your ROI at current prices would be 150% in just dividend payments, not to mention the appreciation of the token price. Kucoin is a good example of how quickly an exchange can dramatically increase its volume in a short period of time. IMO, once coss can stabilize its engine (its still in beta), it will have a huge increase in trading volume as it will be able to add new trading pairs without worry about backend problems.

As others have said, its incredibly unlikely (as in would take millions of years if not more) to crack individual wallets. As for 2FA, myetherwallet isn't actually a wallet per-say. It's an online interface to interact with your wallet. It works the same as if you downloaded a wallet application and input your private key there.

Definitely

Eth,
XMR,
BCH,
Ripple,
NEO