The initial response to the en banc hearing request discussed alternate means of resolving this so IDK.
You cannot be both the judge and the appellent in a case. The En Banc justice who writes the decision will have to reconcile that conflict. You have to be a party to a case in order to appeal and if the court has decided decided that Sullivan has standing to appeal then he cannot then be the judge in the case. That conundrum is what is what faces the liberals on the court if they grant Sullivan what he wants and appellate courts don’t like to be overturned.
The appeals court should not have taken the appeal in the first place and the liberals on that bench are looking for a way out and very possibly a way to drag this case out even further.