Hello Turtvig234.
1) In final version of game: Yes
2) Yes, but if you will create your own server, you will decide what types of skins etc. will be allowed there. Options will be:
a) only official (from AAAGAMES)
b) only official and approved (from AAAGAMES and approved by AAAGAMES = does not disturb gameplay and have high quality)
c) everything (also pink, crazy, low quality...)
3) Yes, new maps etc. for sure. New aliens and weapons are much more complicated, we currently do not plan it, but maybe later.
4) Yes.
5) This is big question, we wanted to have some playable version right now, but it is complicated. We will release more information soon.