question for GC, help me pls!

We just got married. my hu*****and has green card, will be eligible to apply for citizenship in 4 months, I am OPT now (will be expired in 2 months, no H1b yet). I have following wuestions:

1. Would that be a issue when my OPT is over, but still not apply for green card yet?

2. Do I have to apply for "conditional GC" when my hu*****and becaomes a citizen?

3. Can I work legally during the process for the "conditional card" (which has not been approved yet)?

4. How long will it take to change the "conditional card" to normal GC?

Thanks so much for your help!