You IMed me about this....and I missed you. Oops.
I agree with Adam for question 2. But you gotta keep in mind electrical stuff isn't just voltage. It's amperage too. You gotta make sure you have a resistor (that has the correct ohm rating) before the LED bulb. For this reason, I suggest you buy plug and play LED bulbs. They have the right resistors built in.
For question 1, I agree with Hill. Use a normally opened and normally closed relay in series. No make sure you don't royally screw up, what I tend to do is post the question (or SEARCH

) in the the12volt.com forums. Someone usually will post a picture of exactly what to wire where.