Shade
Monster Junkie
Well, I think we really should give them turn undead, so I wouldn't be concerned about that. Perhaps they are tied to a nature deity? Anyone else?
I got so caught up in the turning outsiders/dismissal that I missed that the original had the actual turn undead ability!

In that case, turning is fine.
Sounds fair, so we've now got something like:
Turn Undead and Spirits (Su): A cunnequin can turn undead as if it were a cleric of a level 2 higher than its Hit Dice. A cunnequine can also turn creatures with the Extraplanar subtype, including summoned creatures, as if they were undead. If the turning attempt would destroy an Extraplanar creature it is forced back to its proper plane instead, as if by a dismissal spell.
Like I said upthread, if we go the planar turning route, there's already precedent and no need to over-complicate it with a new ability.
We can simplify it as follows (borrowing from the Planar Turning feat):
Turn Undead and Extraplanar Creatures (Su): A cunnequine can turn and destroy undead as a cleric of a level equal to its Hit Dice. A cunnequine can make up to x turn attempts per day.
Additionally, a cunnequine can turn or destroy creatures with the extraplanar subtype as if they were undead. An extraplanar creature has an effective turn resistance equal to half its spell resistance (round down).