Personally, I don't really know. I like Hal and he's probably the most fleshed out Lantern (right?), though he is the most used and might be off limits. I love John, but we also haven't truly seen interpretations of Kyle, Guy, or the others on television - only really in minor roles in cartoons. And there's also rumors going around of an HBO Max show starring Kyle from Greg Berlanti, so they likely wouldn't use him in the Arrowverse.
Realistically, I think they'd go with Simon Baz. The Arrowverse always aims for diversity wherever possible, and we are lacking in characters of Middle-Eastern descent. I'd approve of him, though, considering I don't know much about him.