I think he'd put away Gavin in 6 or 7. I think Broner would just completely nullify his attacks, Rees's energy and morale would be sapped very quickly by the fact Adrien would just be far too strong up close, he'd counter him on the way in, Rees would be missing and hitting arms and elbows most of the time. Essentially the same thing happened against Kotelnik where he was just walking into stuff and wasn't big enough to be effective, and I know Rees has improved but Broner is a lot faster, a lot more natural a counterpuncher and better inside than Kotelnik. He'd break him down a lot more quickly.
I agree pretty much with your assessment Mand. Not sure how much joy Burns would have with the jab early, its possible it could be a factor. But I don't see a feasible way for him to win the fight like that. Theres a lot of assumptions you have to stretch to get to the idea that would win the fight. First you have to assume Broner can't outjab Burns. Broner's handspeed is faster, that's only one factor but its a pretty tight jab technically that he shoots from out of your eyeline. His jab to the body is hard and keeps you off balance. Also compared to Burns he moves his upper body a lot more to roll with punches whereas Ricky has a reactive defence so you could see him off balance which would allow Broner to get the better of that battle. Then you've got to look at the fact that even if Ricky established the better jab, Broner is a more natural counterpuncher, and in fact Ricky has never faced a good counterpuncher. Ricky does fight to a ditinct rhythm where he establishes his jab, followed by the odd roundish right hand and left hook downstairs before showing more movement. That's exploitable for a smart counterpuncher. Then if all else fails Broner shows the ability to walk down and punish a guy when he's got a feel for what you have. Is there anything in Ricky's arsenal likely to discourage him?