1) Makes no differance
4) If your only interested in PvP, and you said item unlocks are not a concern, there is no reason to farm in PvE at all. Just for cosmetics, you would have to farm gold, how much depends on what armor/items you want. Inscriptions can be removed from any item and placed on any matching item type.
5) No idea, I don't concern myself with that sort of thing.
6) You can use any class, any item you get as a drop for another class you can put in your storage, and any other toon on your account, PvP or PvE can then access it.
If your not a fan of the PvP play style, you could have just purchased the PvP unlock packs and avoided the whole thing.