Is there possible to have a guild where the members can belong to both the empire and the republic or must hte guilds be specific?

I'm thining of creating some kind of healing/lightning hybrid with most focus on lightning. Is that a good way to go? Anyone that have any experience? I'm thining of this setup: http://www.torhead.com/skill-calc#201GhkooZfsbRdkruk.1 Any thoughts?

So Open WOrld Pvp is only on specific plantes, not everywhere?

I am abouty to chose server and have trouble decide if I shall select a Pve or Pvp server. The biggest concern I have about the Pvp-Server is if it's possible to chose to not participate in PvP if I donät feel for it at the moment. Is there such an option?