I know some of those coins and I'm sure there is a real possibility for those coins to go up 3 to 5 times during the next two years, but if you do not want to take any risk then you could probably invest in ethereum and obtain those kind of profits anyway.

However it is even possible that you do not need to invest in any altcoin to obtain those results if you are willing to wait for long enough because it is entirely possible that bitcoin could give you those results during the next years.