TSM, YES on the decals. You can apply Poli Glow no problem.
When I did mine, I didn't detail enough around the edge of the vinyl and had to re-apply within 6-8 months of the initial 6 coats of PG.
Do the poly prep in small sections, wash it off immediately, don't let it dry.
Rubber just clean with soap and water, dry, and apply 303 PROTECTANT on it. Don't Poli glow your rubber. Vinyl, plastic, anything that is fiberglass, but no rubber, and not the aluminum (if they are) basement doors either, Maguier's the basement doors.
You have a great plan, good idea.
Kent - 2014 Fleetwood Expedition 38S 360 Cummins
With Ferbie (ShihTzu) Lilly (Pekingese) Memoriam: Katie, Spencer, Zoey, Susie, Angie