Just a couple suggestions regarding some native tribes/confederations during the FIW.
Pentagouets (Penobscots) : theoretically neutrals, but from 1755 on, there was a scalp bounty on them issued by Spencer Phips (Boston) who refused their neutrality status.
So they should be pro-French during the FIW.
Please take a look at the following link :
http://www.abbemuseum.org/phips_bounty.html
Catawbas : used as scouts by the British during the FIW, so they should be pro-British.
Chicachas (Chickasaws) : definitely pro-British, so this tough warring tribe shouldn't have the possibility to side with the French.