Conor will be the clear betting favorite. Because Vegas/bookmakers only set the baseline odds, the rest is shifted by the actual betters. The more people bet on one of the fighters, the more odds shift on his favor. And there is good reason for that. Bookmakers try to minimize risk. If one of the fighters is the slight underdog and most people bet on him, in the event he wins - bookmakers will lose a lot money. That's why the odds are being shifted dynamically so they are balanced. And this way whoever wins - the house always profits.
So basically Conor-Tony should open at 1.90 to 1.90, since it's 50:50 fight (in my opinion). Since Conor is way more popular and Tony is somewhat obscure to the super casual fight fan, most people will bet on him. The more people will bet on him, the most his coefficient will drop - to around 1.60 probably to 2.20 Tony. And this way if newer casuals decide to bet, they'll see Conor as the favorite and would think - "Oh, yeah, it's obvious, let's put some money on him", shifting the odds even further on his behalf. But that doesn't mean bookmakers didn't believe it's 50:50 fight in the beginning.
P.S. If Tyron Woodley was like 10% as popular as Conor, he would have been the clear betting favorite vs. Usman. But since hardcore MMA fans know who Woodley is and who Usman is, the odds for this fight better reflected the reality. For stars like Conor odds don't reflect reality even one bit. That's why he wasn't as huge underdog versus Mayweather as he should have been.
