The Adopted Trait doesn't work like that.
It allows you to choose a trait from the race trait list (such as Warrior of Old (Elf) or World Traveler (Human)).
The bonus feat humans receive is a RACIAL trait, not a RACE trait. Two completely different things despite similar titles.
With no 9th level arcane caster in the party, an Eldritch Knight might be an interesting option for you.
I think Skull'n'Shackles had it mentioned that it is very low on guns by default and by intention - guns are supposed to be a guarded secret weapon of, well, certain powerful groups and people. If your DM is okay with introducing more treasure like that, a gunslinger is ok. A ranger or hurler is fine, though with a bard and a druid I might be tempted to go full melee and show those average BAB scrubs how a real warrior gets things done with a barbarian or a battlerager.
An Alchemist - perhaps with a Master Chymist for a bit more melee focus - is also an option, and can imo be fun. Both the regular alchemists and vivisectionists can find their combat style to be quite handy - bombs are nasty on a ship, and there will be plenty of ways to make your sneak attack stick. I'd say an alchemist/master chymist is a solid frontliner with a pretty dangerous ranged attacks when s/he has to.
Have you considered a swashbuckler type? High dex does not have to mean low damage, and it gives you excellent ranged ability. I've found a well-built dex-fighter makes a good switch-hitter.