Fei can be changed to Futoshi or Heitachi. Futoshi is more versatile while Heitachi is more solid and has one more damage. Ella is good, but she is so passive, so you may prefer Brittany to force at least 1 pill from opponents sometimes.
I'd argue that Ella is just plain bad. She's good for nothing other than 0 pills, and the min 4 on her ability means that she often doesn't even DR to full capacity, and without her bonus she is ghastly. She'll rarely be much more than a liability.
Tsubame doesn't really do it for me. If you want a 5* FPC that isn't 450k, I'd use Yoshida.
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