I had to wait 2 years after becoming a Realtor to make a purchase, because I didn't realize that changing my occupation (even though it was little money) would prevent me from obtaining decent financing. 

If that money runs out, Medicaid will step.To prevent abuse, each state has stringent rules including "look back" periods where the state can disqualify someone based on the transfer of assets.

Tenant's General Responsibilities: Tenant, at Tenant's expense, must:pay any periodic, preventive, or additional extermination costs desired by Tenant, including treatment for bedbugs, unless otherwise required by law;"I would double check, but as long as you have been reasonably proactive to try and help with pest control, the tenant doesn't have the right to cancel the lease for pest issues. 

Also, you can only get a commercial mortgage under an LLC, preventing you from using FHA or Fannie Mae loans.

But learn from this experience, an ounce of prevention is worth a pound of cure.

If possible, I would move the stove, this would prevent grease splatter on your guest while cooking (ouch!)

It is my understanding that clauses disallowing sublease agreements don't prevent a tenant from hosting short term stays.Lease must specify that short term rentals are not approved.   

Him not being licensed may not prevent him filing a lien, and even if so, it would likely take you a long time to get to court to remove it.  

Could I upgrade my personal insurance to prevent this in the future?

Because of the Hurricane the Insurance companies will be imposing moritoriums on their agents preventing the writing of new business until the storm is past.