I'd say I'm warming up to Hilda as an echo. I really like her, and if you look at my Smash mains, you can clearly see that I can't be against it...
I don't really believe it's likely though... But despite her design being really close to Zelda, there's things to give some unique look. Thorns instead of crystals on Nayru, a soldier coming from a painting instead of the Phantom (TP Zelda already borrowed from another timeline, I don't see why Hilda can't borrow from Yuga), and summoning Yuga-Ganon as a Final Smash. Just quick ideas.
I'm not really sure on how to implement the staff though. Even if Chrom have his own Up-B, I think that echoes will always copy normal moves.