1- Don't know really, it may be you have to wait for your supercustoms patrol to read through all the manual
2- Well, they make rather good arrow catchers, but shouldn't hit the broadside of a barn with 8 att, and get killed fast with 9 def when against any "good" unit.
But they sure can handle indies ..
3- Yes, "patrol" puts the troop outside castle. But no way to have your mages join an "outside" fight if they make research or anything...whereas they do if they're no castle !
4- It works like Astral Communion !
5- Succubi are better than Oriad, but don't seduce that much. they make really good assassins though
6- Yes, it's a nice spell, it can give you valuables units. There's a standard MR save, so it's hard to have really powerful units with it.
7- Some pretenders gets summons based on something else than Dominions (ie the Niefel Giant gest Wolves according to cold scale), but maybe there's some randomness too...