Without Pogacar and watching Malhao's sprint and Pidcock in Andalucia, I think Del Toro win Flèche Wallonne easily. Ayuso has a good punch, but he seems more beatable. Pidcock has a lot of punch, but he might arrive more coocked because he'll be leading every race until then. But he'll undoubtedly be his main rival.
Del Toro seems to be even faster. I don't see any other contenders than Pidcock and Ayuso like third contender. And nobody is capable to break the sprint like Pogacar did, unless Remco attacks in the penultimate climb, which will be his only chance to win, but that's not good for him before Liège.