Let me lend you a hand with these questions. Wouldn't want you to have been left empty-handed!
1) Yes, the game will be on Steam. 2) Officially supported? More than U3. 3) We've already talked about this a lot. Short answer: yes, less limited than U3, yes. 4) Already implemented (with a screenshot of it on Devlog #039).
5) Devlogs aren't scheduled. That being said, we typically do announcements (if we have any) on Fridays. The next Unturned II update is largely just a minor patch to the last update. You'll have the next devlog relatively soon.