AtriumCompound I guess my question is whether google has has a whitelist of devices allowed to run play services based on which OEMs have licensed it
They might have a list, but I don't think it matters regardless. They don't block OEMs. Even rooted OEMs are technically allowed.
Graphene1 I'd guess they could apply Google's SafetyNet attestation to their services
If they did that it would mean losing users, which would be counter-intuitive given Google's main business model depends on harvesting data.