There is no way Castellano would have made Gotti an underboss--Gotti's loyalty to Neil, and the drug dealing, were tremendous liabilities to Paul, especially since he was facing a RICO trial. And, there is no way a co-underboss situation would have worked between Gotti and Bilotti, whose loyalty to Paul was unquestioned.

As for DeMeo: If Gotti had the balls and resourcefulness to whack Castellano without the Commission's approval, he would have been able to deal with DeMeo.