Heyo,
So far it looks like you have a solid concept. There are a couple things I'd like to comment on before you get too far, however. For the Ember Celica inspired vambrace, I'd recommend mounting it more like a small buckler shield onto a separate vambrace, rather than having it be the vambrace itself. It'll help to divorce it a bit more from RWBY and bring it more into the realm of SWarzy. To be honest, I looked at your sketch and my mind went "that's Ember Celica", without even reading your post. It's fine to take some inspiration from other universes, but that inspiration needs to be kept very subtle - almost to the point where the viewer has to be blatantly be told that it's present. Pretty much one of those things where I can "borrow" Blake's colour scheme, but the minute I start adding cat ears and a Variant Ballistic Chain Scythe, I've gone from inspiration to crossover.
Backplate-wise, the design should work as long as you have a minimum of 2/3rds of your back covered. For the thrusters, I'm not certain they'll pass muster, especially coupled with the Ember Celica-esque vambrace. It might take you too far into crossover territory at that point. However, if you are set on having them, I'd suggest talking with the App Team, as they'll be the ones making the final call, and your Ruus'alor, as it's their job to help you stay within our CRLs during both initial construction and any additional upgrades. Also, jetpacks are not a required item(unless you're building a canon character), so nothing says you need to have one. However, if you want one, and don't want to use the standard Fett, Deathwatch, or Rebels styles, custom designs are approvable provided they are sufficiently SWarzy. You can also have jetboots similar to Cad Bane, if you'd like.
