I agree fully.
Interesting, because we seem to be saying two different things.
I’m saying we do know how they affect the din – it’s only muttar if and because they are ???? ??? ????. We may not know which physical characteristic is considered ???? ??? ????.
We also know how 12 months affects the din, just that the Chazon Ish explains that the specific treifos the Torah considers treifos are the ones which during the time Chazal codified it caused the animal to die within 12 months.