Need about 10 coins
I am thinking
Bitcoin
ETH
ADA
XRP? Not sure
Stellar Lumen
Why do you think that those coins you stated is a good coin to hold for long term investment? did you made a research about each of those or you just saw some people talking about it and decided to also invest? Diversifying your investment is not a bad thing, what is good about it is, it can lessen the risk of losing huge amount of your investment, but you don't have to put your funds to us many coins as you can, 3-5 cryptocurrency is enough as long as you can manage all of them at the same time. I will not recommend any coin as what normally I do, because as an investor, you should know on where to put your money, understand the purpose of the coin and if you think that it will be big in the future then go for it and of course consider the security of the coin, if it is weak I would never invest on it.