[Jpenn]

1) My build right now is 3142; I've made up my mind to change my build graph when I reach 3rd job because I'm more of a pvp-type. However, what build should I change it to? I was thinking of 1144; however won't I lose a lot of AC/Gun dmg?

whenever you're going to be a hybrid, your sacrificing something.
in this case its AC for LK, or vice versa I prefer LK to AC because I can always debuff. if you're dead set on 1144 2 AC/2 LK is a good compromise

2) I'm currently Pure AC. However, should I start adding LK so I can be a hybrid AC/LK (since LK would be good in Pvp).
yes.

3) Through 1st job -> 3rd job, should I use a gun or a dagger? Stone Strike pisses me off with it's bad accuracy; however I can be a melee fox to make up for it.
dagger, since all of you damage skills until 3rd don't include a gun

4) What should I comp on my equips? I know this depends on the build; but I want something good for a gunner fox (at least to help me survive pass the 3rd job trails xD)
what catharsis said
LK for mages and other sense chars, and AC for buffs (i'm not even going to mention bunnies :/)
I'd also like to add. get a LK shield and cane for when you go melee ( icky + pistol whip ftw?)
and an HV set to dodge people