Peirera fights foolishly but that style can get him some fluke wins against decent opponents for sure. He's got some good hands though, his left hook to the body looked nasty, he should probably focus on making his opponents tired to the body and then catch them with the acrobatics.
Hall looked good, good boxing and a very good jab, if he ever gets a fight with Adesanya, which seems unlikely in the near future, it would be a beautiful fight although Hall would get washed.
I think Gaethje has a chance against Khabib, he's got that brawler style where he'll keep Khabib on the feet long enough to tag him and he won't panic under the pressure.