One thing I didn't see mentioned is making sure the number/dialer you're calling from is being marked as spam/spam likely or outright blocked by the carriers.

If so the carrier has the right to deny any/all claims you make or if they want to be nice they will settle the claim and retro charge you the premium you would have owed having the proper policy in place when you started renting it out.Talk to a legit local agent and tell them what is going on and get them to run down all the exposures you have and what you could do to best protect yourself for the best possible premium.

He emailed current carrier asking if they could re-write current policy to me.

Most insurance carriers provide so not hard to get.Hope that helps.Best of luck

What carrier?

I would see if companies like first american and other large title insurance carriers have courses (see below).First American Eagle Academy 

@Sarah Kensinger hey I must have tried another BP advertised carrier.

From my experience landlord and homeowners insurance are different.I got quotes from all the big carriers and found the best rate with State Farm.

Most carriers would non-renew in this climate to take it a step further. 

With that info, thats very easy to calculate.Insurance will pretty need to get your insurance carrier to provide you with some quotes.Aside from your mortgage, that handles your PITI.Everything else is part of the rest of your due diligence.