If only power is the only factor and measurement to be the best of super-lightweight division then Devin Haney wouldn't have any problems but he shouldn't forget that it will be a new weight for him and a new division as well, and while he's still adjusting to the weight, his opponents like Regis Prograis who is more comfortable at 140 will not show him mercy just because of that. Haney does have a chance, I'll give him that, but not as decent compared to the one whom he will face. And Teo Lopez? It turns out that he's just an underrated boxer who actually does have a chance to be one of the bad guys at 140 and let's not forget Josh Taylor, I think he can still bounce back.
Haney is high technical and has reach advantage, so I don't really think different weight will give him a trouble.
Prograis, Matias, Romero and Lopez aren't high technical boxers, so it will be pretty hard to beat Haney. Well maybe Josh Taylor has a chance to fight with Haney even though he not own any title, but his last performance against Catterall and Lopez were not good.
Lopez actually an overrated boxer due to his popularity, he's strong and has a stamina, but his performance is just not stable.