can I make a facetime call while blocking my number can we talk if someone calls me without identifying their number but I still accept the facetime call
No - FaceTime is peer to peer and exposes either your phone number or AppleID / email to the caller.

You can of course accept the call, and they will know someone has that account. And by virtue of answering, you have confirmed the contact they dialed has someone looking at the device and signed in.