1) In my experience, usually only the number is displayed when the phone is ringing but not during the call.
2) Make sure on you phone you have Google Now turned off, otherwise your phone will try to search Google products first rather than your contacts.
3) No, not at the same time. It will pair with the first one it sees.
4) I've had it for 4 years and it's been great for me. Does what it says it will do.
Hope this helps.