I can't see the harm in giving your cat some turkey for a treat, after all it's just cooked turkey, yes? Ok I'm just a newbie to the site, but my cats have often had some cooked meat for treats.
My new cat Bibby has Orijen & VIP Fussy Cat dry food with treats in between that include cooked chicken (boneless).
So yeah, go for it.
Peanut butter? are you sure you mean your cats, not your dog, like peanut butter?? my childhood dog loved peanut butter, it was a hoot watching that tongue slurping..I never heard of a cat liking peanut butter. I understand yogurt, for sure. I have found that some cats LOVE dairy, and some have NO interest - there seems to be little in between.
I have been getting the low sodium deli turkey. However, in light of the hairball issues, maybe I will just boil up a plain chicken breast and give them that for treats.