FaceTime on Macbook without iPad interference
No - there's no cross talk possible since Apple uses different encryption keys for each device. All of them receive a notification / offer to start the call and continuity would allow you to hand off a call from one device to the other.

If you're distracted or worried, you can sign out of FaceTime / Messages on the device you want to be sure isn't bugging you, but architecturally - there's no downside / benefit to having more than one device signed in other than if your network can't handle the signaling items or can't NAT the traffic correctly.