>>926074261. Gura and Kronii knew each other before, that is confirmed by their Bitch Lasagna covers (comments section).
Mumei and Fauna knew each other before, too, I believe. Gura and Ame is not directly confirmed but possibly, as well.
2. More than you can imagine, actually. At several previous works I had multiple friends, granted we were friends only for so long because I am an antisocial cuck and prefer to stay at home mostly. But even my introvert ass was able to become friends at my bitch ass software development jobs.
3. Fauna is graduating in few days - I think it can justify making some time for a fucking one hour. No one even asks them to stream, just tune in and be there.
At my jobs we never ignored the goodbye parties for people that were leaving. Somebody may be ther only symbolically, leaving after an hour or so (because children etc) but no one just outright ignored teammates.
4. Yes, we know that Fuwamoco have no shame and do not care about their genmates.