Ok for the switch keeping the knob hostage it is because the flat parts of the assembly are not all lining up. Look down the housing and make sure they all line up before you "stake" the knob. I have broken one that way,I like to test fit off the truck then put it all back after the test was good.
Here is my tech hope it might help you out:
http://www.jalopyjournal.com/forum/...on-a-delco-remy-headlight-switch.940829/The dome light should ground on the housing much like HRL said. Same principle as the tail lights.
