Welcome:
1. No idea
2. Sounds like the floater is shot in the gas tank. It's accessible through the trunk.
3. More than likely the contacts are corroded. Take the switch off and then clean the contacts really well. Usually will resolve your problem.
4. Have you tried resetting the oil life monitor system yet?

Shat do you mean the trac button does nothing? Like you push it and it doesn't illuminate on the DIC?