I posted this in a different thread, but I think it's worth repeating.
Regarding Wolverines costume, I think there's 2 way they could introduce it without it feeling corny.
1) Wolverine has a brief flashback to the glory days of his colorful costume escapades. Like literally a 2-3 second flash of him posing, then another one of him attacking something.
2) X23 can have a dream sequence where she imagines a "fantasized" version of Wolverine where he goes full 90's with the classic costume and dialogue. It won't feel too out of place if it's a dream, and it will stay in context with the character, as she's already a X-men fan girl.
I really started to fall in love with the X23 dream idea. They could go full 90's with it, and just have her wake up in to the grim reality of the Logan movie. Doesn't have to be a long drawn out jarring scene. 30 seconds of action and comic book dialogue would be enough to please fans.