I've bought 1BTC in december 2016, now I read that has some problems and it might collapse.
Where did you read bitcoin will collapse, can you share that link?
I want to invest in a new project, but i wonder if next day after sale the devs disappear, I will be able to sell my tokens?
If devs disappear they won't run before they dump all tokens, so you will probably sell them for less money you payed for them.
Or if for some reason I'll need money how I will be able to cashout if they are not listed anywhere?
If there are not listed anywhere than how will you sell them? I don't think anyone will buy unlisted tokens after ICO.