Maribelle Makes a beastly Dark Flier Lucina, the only problem is that Brady doesn't get much from Chrom.
Chrom!Brady is no Chrom!Inigo or Chrom!Cynthia, but he still turns out okay. He already gets Galeforce/Luna/Aggressor/Tomefaire to be a strong player phase Sage. (who his sister Lucina can support) Rightful King is also alright with Miracle and Aegis.
Sully's actually the worst plot wife if you don't go for supports. I'm going with Olivia.
At least Sully had some kind of relationship with Chrom (they were childhood friends) and Chrom knows Maribelle through Lissa and the fact that she is a noble before the game started. He barely knows Olivia (and FeMU, but MU can be male and she has more time to develop a relationship with Chrom).
you've made your point like 5 times in this thread already. quit it.