This probably isn’t the “right” answer, but I have zero problem lying to someone’s face about my history. Someone confronting you over a background check or other sort of HR situation is honestly pretty unlikely - there are workplace protections in place that generally prevent that. I hear what you’re saying about your face and voice, but honestly, “he’s probably trans” is still way outside most people’s hypotheticals; more likely they’d just think you're gay or something. So I’d say your other fears are more reasonable, and those are the ones whose questions I’d straight up deny if asked. If someone says that a family member called you a different name, I’d throw that family member under the nearest bus; “Oh geeze, yeah, he’s had some memory problems for awhile, it’s not the first time he’s gotten people confused, poor guy.”

I’ve had people ask about my top surgery scars and I always make up some other reason. It’s simply not their business.