If I get a cellular watch and use family setup, will the watch pair with my phone at all?

I want to use the same Apple ID so I can send and receive iMessages. I realize I’ll have to use a separate number for calls and SMS, but am I required to use a separate Apple ID? I want my fitness data, podcasts, etc on my phone synced with my watch. Is the only way to do this by pairing it in the traditional way?