Void - Battle or Tactics would be ok.
Dimension step/Hop would be OK.. after all, it'd be kinda unfair of me to tell you you couldn't use something that I allready plan on some of your enemies using.

I'm pretty open on Dieties, just tell me who/what it is and their available domains and i'm 99% sure it'll be ok.
Shayuri - He wasn't talking about Dimension Door, but Dimension hop and Dimension Step, which are low lvl short range teleport spells from the PHB2.
All - As to them coming 'prebuffed', all of their spells that you didn't WATCH them cast have minimum of 3 hour durations. I fail to see what's unfair about a party of adventurers travelling with hours-long duration buffs on. Much like I said to you earlier about including your 'buff lists', I keep in mind the same thing for NPCs, meaning all those 10 min/lvl spells they have on are taking a toll on their spell slots.
As to Disjunction - As I've said before, and will say again: I won't use it until you guys do. Mutually Assured Disjunction.
Rathan - Sorry I missed the 5' step question. The answer is: A 5' step can be taken as a FREE action once per round, but cannot be used in any round where you Actually move (via a move action). Meaning if you are just doing a full-attack, you can 5' step before or after your full-round.