Casimero could potentially face either Donaire or Inoue if he wins against his challenger, it's a task he cannot say no and he cannot lose if he wants his dream to be realized.
I think he will likely face Inoue as his promoter would not allow that to happen.
This is probably the scenario.
If both Donaire and Casimero will win against on their respective challengers, then one of the could fight Inoue, if one of them lose, at least there's still one left that could fight Inoue, in that way, both fights would give good money to their promoters since Inoue is popular and he will attract the fans to watch the fight.
Both Donaire and Casimero are now under Probellum and they have become friends already as the Donaire's were the ones helping Casimero to land in Probellum so I think the probability of Casimero vs Donaire is slim, it would be Inoue fighting whom they think will give Top Rank more money.
Butler had a weak chin, this would be Casimero's target come fight night.
Watch below the KO highlight of Tete on Butler.
https://www.youtube.com/watch?v=SKO_hy91rx8
Well if Butler has a weak chin then it will be over for him once Casimero touches that chin.
And we all know that Casimero has power in both hands, so I don't know how long can Butler avoid that. Unless me might run like Rigo and it will be a total disappointment for the fans.
Probably the big target here is Inoue, regardless as to who get it first, Donaire or Casimero.
Thanks for the link though.