Welcome to FUD @Vic !
Probably the best way to accomplish the Libre to Pebble combination is with xDrip+, an open source Android app.
I personally use the Dexcom G5 with a Sony SW3, and I really don’t know very much about the Pebble. But I do know that the developer of xDrip+ uses a Pebble watch.
I think that one of our members, @jroth , is currently using the Libre with Nightrider and xDrip+. Hopefully he will chime in.