My best guess -
The email and bitcointalk account are from the real owner, but his email was somehow compromised, so the imposter can reset the details and gain access to his bitcointalk account.
The phone number is not from the real owner and was registered with a fake name by the imposter, that's why when people do reverse search, it shows as the real owner's name.
The email is a work email, and it is not going to remain compromised for an extended period of time. Anyone can create a bitcointalk forum handle of anything they want, so the bitcointalk account may or may not be compromised. I think there is a high probability the phone number actually belongs to the person the OP is claiming to be.
So no matter people try to contact the person via email or phone call, it will all ended up answered by the imposter.
OP said he will share his personal ID via video call, but it's impossible to do a video call via email or a regular phone call.
You can facetime with both an email and a phone number. Ditto with other video call services.
Another red flag: The real Wolfgang Kainz is a biomed researcher who merely works for the FDA (
Linkedin).
The OP's claimed email address clearly indicates he works for the FDA.:
wolfgang.kainz@fda.hhs.gov
