Then, they finally call you because there are no more reserves left in your account, because they spent it all on "emergencies" that they didn't need to call you about because they were emergencies or all under $250 or whatever.And, you will have to manage the manager anyway, if you are smart.So, 1) manage it yourself.  

Accelerated rent is all monthly rent for the rest of the lease term or renewal period, which is automatically accelerated without notice or demand if you: (i) move out, (ii) remove property in preparing to move out or (iii) give oral or written notice of intent to move out before the lease contract term or renewal period ends.

I used to be very enthusiastic about it, really gung-ho and I'd do research for two/three weeks solid looking at deeds (liens) on many of the properties.I once gave a tip to a friend that if he got the property we would sell it and split the value minus his costs, it was oral deal (he was good friend), I could not afford the lien ($1700 plus subtaxes for three years), he ended up getting killed by a car crossing street.

Nothing is perfect or all good and no bad.  

You could offer to fix some or all of it, but advise them that the process of them moving in will delay and we will have to postpone the lease to make sure that the items are corrected before they move in. 

I guarantee that most of the successful investors in your local market, who have been around for a decade or longer, have purchased some or all of their properties using debt.

Should I send a letter, phone call, in person or all?

Thankfully5-day notice to vacate to tenant at willThis notice can be used only if there is no rental agreement, oral or written.

Would they contact me to refund any or all portions of that?

Get him to state he has an oral lease in writing (letter, email or text) with dead husband, then evict him (oral leases are legal in Florida) plain and simple.