Well first off, yeah youi're rendering skill are quite impressive. take that effort and apply it to the physical armor and you'll be approved in no time. Seriously good work.
Not an app team, but I've been a ruus for a while now, so I can give some educated feedback on most of things.
Helmet shouldn't have an issue. most I could see would maybe be them asking to simplify the horn detail? Most of the helmets we see with similar adornment are more basic blocky, this looks almost to akin to halo style. It's def close enough that i've youre happy as it is, drop it in the app q&a form first. I've been proven wrong at least twice in my life... maybe 3 times but i stopped counting after that

chest armor looks fine. you've got paz visla with some greeblies. I dont see much reason it wouldn't be allowed.
The boot armor is a bit too close to halo for my liking. I'd suggest an altering of the toes a bit so it's less spartan like.
I also dont see any reason why the ren blade would be an issue. lots of folks carry their axes, or variations thereof. So again, worst case just alter the blade geometry, and or add a few more greeblies or plating layering for aesthetic.
If something was unintelligible I do that sometimes and apologize, but feel free to reach out with any questions! cant wait to see this take shape.