Both have waaaayyy too much going on. You might want to specify like max. 3 sub-themes to your fic. One that is most present and 2 sides. I know that myself, as a reader, don't like it too much when the author keeps on changing the enviroment or mood way too much. It would feel distorted and bi-polar. I would also pick elements that fit another. I can see how mystery and gangs would fit, but rom-com in the same fic with gangs would feel so out of place. I would say option A would blend better as a whole, all together, although the 'revenge' thing pulls me more as I like darker stories more than school/acemedy ones.