I would've gone with “Mary”, as “マリア” [Maria] is the Japanese name for Jesus's mother. Tho, “Maria” is certainly defensible on foreignizational grounds. Most people will not understand the 1:1 naming scheme tho, and I think that's a loss. There's a clear Jesus parallel with Kiritaka.
Edit: As of Chapter 2, I no longer agree with this and think “Maria” is the way to go. (They reveal her maiden first name is literally “Maria”).
As for the chapter itself, there's definitely a straining of suspension of disbelief with the insane bullying (as is often the case), but I think that's not gonna be an issue. If the series is more serious, this will probably just be the inciting incident and not much more. On the other hand, if her revenge becomes insane too, then this was just setting the baseline. Either way it works. Or maybe I'm just being too optimistic. I dunno. We'll see.