About Marisa...

Swordbreaker would be better because although her spd is good. It is not going to be enough to double units like Ayra and Mia. I prefer Wind boost here because you are only at 39 spd with refinement and you will struggle to double without Fury or swift sparrow. For SS, I think Speed sacred is the best option, as I mentioned early she needs as much speed as she can get to double.

I don't really know what to tell you. The "common red sword unit" builds tend to be practically every build that's effective.

I mean... she's similar to Joshua, she has a lot of speed, and a lot of defense, so you could make her a speedy, bulky unit. Swordbreaker is a good B skill because that, mixed with her decent defense stat, can save her life. I wouldn't do Renewal since I'd have her in the back, waiting for the right moment to strike, rather than trying to engage enemies at full/"non KO" HP. Infantry Pulse for obvious reasons is a good skill, and you can run something like Close Defense for more bulk, a speed seal, pretty much anything you feel like she needs.

Wind Boost with Atk forge seems better for her imo. Either is fine for B, but Swordbreaker might be a little better, especially if you have a healer or pseudohealer on your TT team.

I really like your build but Im not a fan of breaker skills, they seem too specialised and I honestly would never initiate with her on a swordunit anyways.
So I was thinking about other ways to use her and came up with this enemyphase version of your build:

WoDao (+Def/Spd)
Repo
Revenge/Reprisal
FireBoost or Fury
QR/Guard
Infantry Pulse
CloseDef/QR

This build would use her high hp, which is the only thing she reeeeeally shines at, to deal damage. Similarly to Ayra and her speed, but not every character can have a broken special, so I tried making the best out of what she has going for her. (Tho I wouldnt run her without a healer).