I will need separeted users for each website it will be possible? It's like I'll have 3 websites with diferent users for each one, one user can only login on site1 for example.

I will need separeted kunena fóruns on each website it'll be possible? And if i wanna one kunena forum for all the sites, is it possible too?

I will need one separeted JCal for each website, it'll be possible?

I will need separeted articles for each website it'll be possible?

I will need a separated project fork for each site, it'll be possible?

I will need one separated DOCMan for each website it'll be possible?

Thank you.

By default, the content of each website is independent.
So the users are specific to each website.
You need a specific action when you create the website to share the users.
See the tutorial video 16 that illustrate how to share the users.

Therefore the forum is specific, articles are differents, ...
In the case of DocMan, if you share the same "dmdocuments" directory, they will be shared but you can also decide to have a specific "dmdocuments" for each website.