Dubois would beat Byran I'm certain. Chisora-Dubois is a 50-50 fight. Prime Chisora would beat Dubois, but perhaps not now.
I don't Dubois will face Bryan in April tbh. Seems more likely he will take a stay busy fight and fight Bryan in July. Hrgovic vs Zhang is an awesome fight for the undercard of Canelo-Bivol.