Eric-Jan,
In order ('cause I might as well...)
1. Yes, exactly.
2. The PP event system that was developed at the start of 200(8?7?) takes care of someone else locking your plane (by flat stopping it... you get a personal and private B1900D for the event). Even if someone does manage to lock your plane, there are always standby aircraft available and a management team that keeps on top of such things

3. By tradition, we hold an online "fly-in" for the first leg, then it's up to the pilot. I like to fly PP events online and with real-world weather, others are happy to fly the event "offline" (being PP, you currently require an active Internet connection while flying so our server can "spy on you"

but you don't need to be on IVAO/VATSIM unless you want to be)
4. Depends on the event. There'll be a suggested route (no doubt) but as with all such things, if you go a different route, good for you.
5. Only you Eric-Jan, only you. We've gotten events down to a fine art now; planning them (and participating, of course) is what takes all the time, assigning aircraft etc takes a few hours only and is done but once.
Oh, and put me on the "list" for the event please Bruno... I'll see if I can't make time to participate.