I think that you fill this up with original characters, even parodying famous characters can make the story mode quite fun just for the absurdity. About the gameplay, the normals still seems kinda clunky and most of them don't link into other normals, except into themselves. With that said... here's my tier list for the original characters!
Tier S:
Kat. This duo is just too powerful for this universe. Both their fireballs have almost no recovery frames and they hit knocked down oponents, which causes an infinite just by spamming the fireball from anywhere on the screen. pls nerf
Tier A+:
Adrian. The exhibitionist is not far behind the duo, since she can also stunlock her opponents just by mashing Down+HK. Unfortunately for her, this only works at medium range, so she will stay behind Kat.
Tier C:
Yeah, the Stickler got the short *stick* in this one. It has good normals, with good range and speed, but still get ouclassed by the two monsters in the top of the tier list.