Evan McMulllin, I think,
Rudy doesn't like a special counsel, and Sidney just left Trump's team because she was more effective on her own.
An Trump appointed SC under a Biden Administration would be hog tied like ken Starr was.
Something else going on, I believe. I don't think any major information at this point would be passed over signals infrastructure. It would be face to face. SC is a bone thrown to the curiosity seekers to keep them occupied, or part of a canary trap.