I like Gwenhwyfar Maia but I don't think she'll end up on top in the UFC. She's reasonably good most places but not really outstanding anywhere, except for her cardio which is great; if it wasn't for her cardio she'd have lost her title fight vs Porto and possibly her defence against Niedzwiedz as well. Unfortunately, I don't think she'll get the chance to fight a 5 rounder in the UFC. Carmouche isn't great anywhere either but she is bigger and stronger and could grind out and least two rounds. Her grappling approach matches up well against Chute Boxe 'Brazil-Thai' style on paper.
Maia is a little more skilled and her championship experience has also given her the nous of when and how to do enough to win rounds on points. I hope Maia wins, anyway. Preferably by single leg -> back tack -> nosebleed inducing RNC