Girls from Gravity Falls can also be in this. Pacifica, Mabel, and Wendy.
Girls from Ben 10 are Gwen, Kai, Lucy, Sunny, Charmcaster, Julie, Verdona, Rojo, Tiffany, and Fright-wig
That's it for now and I don't mind adding more
I'll check it out if I get the chance, honestly does look pretty funny and characters look fun. Also a futuristic setting could work, but had me mind on a anime type school concept with Ben being the main protagonist and getting into ecchi stuff with girls. Also have you heard of Ren'Py?
I haven't seen Konosuba yet, but it's seems to be all over the net recently.
Also Ben 10 in a harem school scenario with the girls in the franchise, what do you think?
Yeah, honestly it's a guilty pleasure for me, also the manga is better because it actually has a story unlike the OVA. I own both mangas and OVA and hoping to get the rest someday.