Skeptically, "if the parts can handle it" would be key in my view. How do I know true tone and battery health would be in any way accurate, if they're using who knows what display, and who knows what battery/BMS?

There is never a guarantee that a third party part works identically to a first party part regardless of what device you are repairing.

You're saving money, but taking a chance.

I agree with you. Hence why I’m saying this supposed statement by Apple isn’t really saying anything. They’ll allow it to work, but probably none of them will actually support True Tone since they don’t know what proprietary secrets Apple has for their displays. Not really apples problem.