A deboned/descaled tilapia will be fine. Better than no fish. Just give a bone in meal the next time. At my local grocery store, they have a 5lb (i think) bag of whole frozen tilapia in the same section where they had deboned filets. I did not see them the first time I looked, so maybe check again? Then again, my dog wouldn't eat a whole tilapia. I havent tried a deboned and skinned one...she might eat that.
You can give chicken/turkey gizzards as more of a muscle meat not organ. My dog eats them, although she doesnt prefer them. She would rather eat a beef heart or regular meat. Again, give those after a bone-in meal, or vice versa.
My dogs love chicken hearts and gizzards as a little snack for them, I don't know that I'd make a whole meal out of it though I'm sure you could, but then my kitties would get mad at me for not sharing!
And as far as raw tilapia goes, it's fine but it isn't as high in omegas as salmon and mackerel are, so I gave up on tilapia and switched to canned fish since it's easier to store and apparently better for them anyway. I'm not sure if it balances out since it's not at good since it isn't raw but at least it has higher omegas? I don't know. Either way, deboned, descaled tilapia is fine.
If your dogs will eat the whole tilapia with scales and bones I would choose that over the deboned/descaled filets. But some dogs find the fins, scales and bones too foreign or weird to eat.
We supplement with omegas, and grass fed beef and game, so I'm not too worried about them not getting enough from their tilapia...considering how expensive it is in comparison to raw fish. Plus I think Bailey and Akasha get a lot of their dental benefits gnawing through their fish because they have to chew them pretty well for them to get thru fins, scaled and bones.