Hey, welcome. Thanks for the kind words!
For creating an ingame account: use FH2 Launcher, hit options and select none / manage accounts and hit OK. When you press play, it will bring you to a bf2 styled menu, just select manage accounts, and then create account under multiplayer tab.
1) If you play on singleplayer instead of coop, the bots will balance out.
2) I have seen bots use artillery, but can't really answer specifically how accurate they are.
3) Yes, scoped weapons are lying around as pickup kits, use "g" to pick them up.
4) Not at the moment
5) Ingame, you can see where the radio table is on your map IIRC.
Best regards,
Roughbeak