is this even shounen ai or yaoi? :/

I think is not both but I also think that it has a little bit of shounen ai in the manga(￣∇￣")

It seems to be a mix. You got the het couples, but the shounen-ai is kinda implied with Maria and Mary.

This manga made me confused bcuz of bloody and maria tho lmao when I'm reading this can't stop to think there must've been a mistake

I mean, the original author drew them in traditional Japanese wedding attire once, don't know if that means something.
Mary was wearing the girls attire and Maria was wearing the men's clothing.