I must admit that I'm a bit disappointed that yet another action yuri thing is ecchi, but I don't care that much since it definitely fits this completely ridiculous manga. I wonder why pretty much every action yuri thing out there is also ecchi... well, I guess it may actually be obvious but still. That said, I certainly enjoyed it 'cause I love ridiculous stuff and I also love vampire yuri, so I'm looking forward to more for sure. Hopefully this isn't cancelled like a lot of other vampire yuri things...
Well Madoka is kinda action Yuri the few times its not being existencial dread
Quick note that "Noel" is typically the spelling of the male version of the name, and "Noelle" the female. Assuming it's originally written "ノエル", you should use the latter romanization.
As far as I can tell, "Noel" is a genderless name. Wikipedia confirms it's used for boys and girls, and I've seen several Japanese characters named Noel who spelled it like that as well. It's also easier to typeset, being shorter (longer names can run into trouble in smaller bubbles)
There are specifically female variations on the name, with Noelle being one of them (particularly in French), but because this is a work of fiction not explicitly set in any one country, I'm gonna go with Noel for now.
I'll change it should the author give an official romanization of her name.