If it is not reasonably dry (and full round branch staves aren't necessarily dry after a year), and you band saw it without regard to compression and tension wood, then it will likely change shape quite a bit when it drys more after being sawn.
I haven't bothered with the bottom side of a yew branch before, but I have heard that is no good for bow wood. Would love to see that proved wrong.
Personally, I would focus on the tension side and make a bow like Pearly's.