Your ideas sound fine; if your opponent can identify their gear and they look plausibly airborne, it shouldn’t really cause problems.
IIRC Scions are more expensive than Elysians. I like them, but unless you’re digging the cuirass, I wouldn’t particularly recommend them.
Saw this thread recently, maybe it can help inspire you.
FWIW my guard also use a headswap with a few additional bits.
https://www.dakkadakka.com/dakkaforum/posts/list/737392.page
There’s also Harakoni Warhawks if you have a hard time making a regiment from scratch.