I know an Isabeau: friendly, bright, attractive, all the right things. But, she's got just the one name.
I'd prefer Isobel, then Isabeau, then Isabel and finally Isabella.
Isabeau Jeannette
Isabeau Celia
Isabeau Margaret - I think it works best with something rather medieval. If you put something really modern with it, like Isabeau Samantha or Isabeau Katelyn, it would look and sound discordant.