Is there any traits for ground eng BOFFs that are helpful, or would they matter for eng boffs? The only ones I can think of would be reduced threat (so Betazoids for fed, and Orian females) for KDF. Also, would the trait creative apply to the turrets and drones that eng BOFFs can deploy? If I read STO wiki correctly, it should.

There are a bunch of good powers, and you should consider them carefully when you make an away team.

Tanking Traits:
Peak Health - HP bonus and toxic resist
Sure footed - knock back resist
Resilient - damage resits
Aggression - Increased threat.

Exploit Traits:
Acute senses - exploit bonus
Covert - exploit and stealth bonus
Teamwork - increased team exploit damage

Expose Trait:
Luck - critical hit bonus and expose bonus

Other:
Warrior - Increased melee and ranged weapon damage
Creativity - bonus damage and healing with kits.

Make sure your officers who have expose traits use expose weapons, and the ones with exploit traits use exploit weapons. Covert is pretty useless on any non-tactical officers because tactical officers are the only ones with a stealth power.

Ultimately, Boff races and traits matter a lot less than your away team build. Having a team with the right skills and gear matters much more than minor bonuses.