House burn down

Dir Sir:

I have a rental house in Frisco, TX that was burn down by my tenant’s son.
The cause and origin of the fire has been determined to have been set by the 24 year old male. He doused gasoline all over his body while in the house. He ignited the gasoline with a small handheld lighter. I already reported this event to my insurance company.

Would you please answer my questions as follows:
1. Should I hire a lawyer to deal with my insurance company?
2. Should I sue my tenant?
3. Should I find any public adjuster to help me to evaluate my loss? Do they charge by fix amount or percentage? One public adjuster called me and asked for 10% of my final check. Is it fair?
4. How do I protect myself to avoid my tenant sue me?
5. Is the leasing agreement (3/2007-2/2008) still good or terminated automatically?

Thanks for your help.
Luc