welcome! to answer question 1: If you wanna be affiliated with a certain faction, as in be an official member of that faction, you definately can, although staying unofficial is more fun for now. You as a person can have different characters in different factions, but 1 character cannot have 2 tags or be in 2 factions at once, i hope im making sense iwth that answer. If you want to have fun with your friends, I would recommend being in a convoy of transports with indie tags, not offcial tags. An example would be the default USI tag to make money. Once you have all the money you want from trading, you can be an unlawful indie group, a lawful indie group, quasilawful, or make your own faction if you want to (the faction will be unofficial at the beginning). To be frank, i think running in a self made faction wiht your freinds is the best bet.
2. I do not know personally how to make a faction, so I would ask on the main discord. For factions that need revitilization, ask around to be honest. IF you guys are crossfire players, then you should be really good at pvp i assume. I'd say that you should look for rp/pvp centric factions. My main faction, the LIA, is looking for members who are good at pvp and want to try rp. We would welcome all of you, but we are slightly contreversial in our reputation wiht other liberty factions, so for now I would say stick with indie for full enjoyment of the game or make ur own faction. I think some of the junker factions are dead and need revitalization, some other factions as well. Again, I would ask around on the discord.
Also, unless you already have, reread the rules ant try to memorize them. It helps make the game smoother so you dont accidentally get sanctioned.
Final note, if you guys ever need help or advice. dm me on here or on discord. my discord is WizardLizard#8153. I hope to see you in game as well.