My question is whether this products get along. I am working a piece with a painted frame and stained shelves. If I get some poly on the painted surface, am I going to get an undesirable result? Thanks for any help you can lend.
No, besides some yellowing there is no adverse effect.
Some people even overcoat paint with poly to extend the longevity.
Which is a waste because the paint usually lasts longer without an overcoat.