use findmy with apple watch se with cellular... even if the wifi connected iphone is far away?

What I am hoping to acheive:

1. Buy an apple watch se with cellular
2. Get it connected to existing tmobile service for my iphone8
3. disconnect iphone8 from tmobile service & use iphone8 as a wifi only phone.
4. Keep the watch on tmobile cellular plan
5. use findmy from the iphone8 or any other iphone in my family to locate the watch and send txt msgs

Is it possible? thanks