Well, what Fitz wants to do is pure conjecture, any way you think to look at it.
One thing though, the idea of mentor, any vet QB willing to share some knowledge or tips, has a better chance of helping a developmental passer than a QB coach who has been a WR coach the past 23 years in a row. In terms of mechanics, footwork and reads, having anyone to teach anything is better than having no one to teach nothing.
Btw, I just looked up Lubick, the assistant QB coach. Guess who else has worked with receivers his whole career ? It's weird.