Just wondering if "prop_physics_multiplayer" is the right setting for props like chairs, tables or crates that you want to be able to jump onto, move with the "use" key but also destroy with gunfire? I think I used that setting first but some of my props moved from where they were in Hammer.

Yup thats the right one for multiplayer stuff. They probaly moved because a bit of the model was in a brush and so it 'threw' its self out (to fix just put it a little bit above the ground; all offical source maps do this, watch for phy objs dropping to the ground on map start)

Also if it's a chair make sure it isn't angled slightly, I had one that was and didn't realize and when I tested the map out it fell over. :)

Same for barrels. I think dressers and tables work fine if they are angled a bit.