Craig Robinson plays piano and has long featured it in his stand-up act, so he really did have a musical keyboard, while he recorded the scene when Shark disguised himself as the priest in the wedding.
To prepare for her role as Kitty Kat, Danielle Brooks watched Inglourious Basterds (2009) for inspiration
The reason why Wolf has been quickly intimidated by Kitty into helping them in the trailer is the fact that in ecosystems where big cats and wolves coexist with each other, big cats are higher in the food chain than wolves and sometimes kill them if they encounter them, meaning that Wolf's fear of her was instinctual.