Dudes is fine - folks and yall also work. I use yall all the time even though I'm now in Canada and have never lived in the US south.
Guys, I think, is still a bit too gender associated but it's borderline. Man is often used in a gender neutral manner but it is very easy to misinterpret and a transwoman could reasonably assume you're trying to troll them.
You've also got fella and feller, I think the latter one is more gender neutral than the former.