Hi Shadix!!
First off....Welcome to the Grievance family! We are very happy to have you on board with the rest of us anxiously awaiting the release of Wildstar!
You had a few questions.... Ill do my best to answer those for you.
Will Grievance be playing Dominion or Exile? We will have guilds in both factions. Grievance primarily will start guilds on PvE realms, but there has been some talk, if the interest is there, to actually have a guild on a PvP realm as well. The PvP realm is undecided at this point in time.
What time zone server are you planning on? This I am not certain of. I am sure another member could answer this one for you though.
Lastly, my gf is super casual but I would love to get back into grouping, raiding, and pvping: basically all aspects of the game. Is Grievance the place for us?
Grievance is a place where you can be the most simple, casual player, or the progressive raider. Each game that Grievance has a guild in has many different play styles. You will never be made to raid, or pvp if that is not your cup of tea. However, we do have very active raid groups in many games, and plan to have one in Wildstar. We have people who PvP, we have people who craft, explore, and others who just want to level. You play the game how you want, but you play it with an awesome group of people willing to keep you company and help you out along the way.

I promise, if you game with Grievance, you will NOT be disappointed. I have been active with them since the RIFT beta, and I can never see myself gaming with anybody else!