Hold on a second -Youmu have similiar appearance with Bea. -Bea is exclusive to pokemon sword version and Youmu is a sword fighter. -Bea counterpart Allister is a Ghost type trainer and youmu is a half ghost and her mistress is also a ghost Ohh Nintendo you smart little girl
When I threw down with Bea in Sword, as soon as the fight started, I went "The things I can't cut with my Excalibur [My Doublade at the time], Wielded by kings [reference to Aegislash], are close to none!"
Now for the part where we debate her team. I'm thinking stuff that has a strong sword motif, like Gallade, Bisharp, or Doublade. (Not Aegislash, shields don't really vibe well with the Japanese martial tradition, plus it's not nearly as effective as it was in previous generations.) To reflect her race's half-phantom nature, we could also do some Ghost dual-types.