It's a very winnable fight for brook, but he really doesn't stand to gain anything besides money, I think. He's already gained any credibility that might have alluded him by fighting GGG, if not porter. Cotto's coming off a loss and now has 5 and doesn't have a strap. So Aside from money and the fact cottos probably canelo'ing around 155 also means it would be a gentle transition midstep rather than Jones'ing himself down and draining himself, he might not get much credit for the victory.

I might avoid the Charlos at first. Those guys got about 3 inches over him and probably come in on fight night about 165+ and would probably try to replicate the GGG performance, and walk him down a bulldoze him. The lesser charlo is probably still easier pickins if brook stays mobile though.

Lots of interesting fights for him though. I'd probably start with someone like Trout. Not a big puncher, somewhat slick, can still be a spoiler, but his legs are probably old enough at this point that Brook can look like a superstar late against him, if not early.