To clarify my question: Is there a way to maintain ownership of a private key even when you intend to reveal it to someone else?
This sounds like one of those "I could tell you, but then I'd have to kill you" scenarios.
To further clarify, I'm working on a concept where proving the initial ownership of a private key is central to the protocol.
That sounds like an impossible protocol. Considering the nature of your question, I don't think you should be developing new protocols.
in the protocol I’m working on, private key collisions are expected to be a regular occurrence.
Are you working on 16 bit private keys? The whole point of private keys is that it's impossible to reproduce random keys.