Can I cautiously raise my hand and say I'm not a fan of Jack? I respect that it's a popular and well liked name, but there's certainly lots and lots of Jacks out there - which is fine!! I personally wouldn't use it for my kids, that's all. And I agree that Jack John doesn't exactly roll off the tongue.

I like Xavier - why don't you ask your friend if he'd mind if you called your son that name (if that's the name you both settle on)? Most likely he wouldn't mind. I really like Ben though. And what about John as Jon? Xavier Jon, Benjamin Jon.