I couldn't comment on any of the stages, so I'm leaving a message here:
I like it so far! I've been looking through the stages and at the Mii choices. I'm not too familiar with WSC CPUs since I don't have it, but I like that Rie is one of the first red armors. Interesting that you made Na-rae the first boss, even though you dislike her.
Are you planning to stick to the format of the official showdown stages? So far you've been structuring them like the real ones and keeping (mostly) the same amount of each armor color, but I remember you saying you were going to add some shields? or maybe new colors of armor.
I'm excited to see what you come up with!
P.S. I suggest you link each stage, something like this: