Darren Horn was recruiting Allen so Jai staying or going probably won't play much of a role in Allens decision. I think Marland Lowe is swaying Allen to Cougar High.
It doesn't seem likely that Jai Lucas is going to be able to leverage his father for recruits, ever. It's not in the best long term interest of JLE to align itself with one school. Promote Jai because he's a good coach and has a history with the program and hope there's an outside chance he gets some casual Intel over Thanksgiving dinner. But dont expect Jon Lucas Sr. to ever be a "resource" for Texas recruiting. He's not going to have a significant impact, if any, on Jai's ability to sign players.
Morrell is a great coach and a great asset to the program. I could see a scenario where maybe he volunteers to "step down" to make room for Jai. But I don't see this playing out where Morrell is demoted by Shaka if it could potentially create discord in the program at any level.