I intend to handwrite the addresses, but print the letter on normal white paper. 

If it already has she should have "Order for Probate" "Petition for Probate" and "Letters of Administration" in her possession. 

The only thing that mildly concerns me is what will my real estate refinance for in 5-7 years, when my balloon payments are due?

This might be related to not picking the right list, your not having realistic expectations, your not having a compelling pitch, or some combination thereof.Don't assume, for example, that just because someone is an "absentee owner" they'll sell you their house for 30% below market value just because you sent them a "I buy houses" letter/postcard.Bottom line, there is a lot more to it then the list.

Ask them to work with you, and tell them you need 3, 5, or 7 years to pay them out with whatever you can negotiate (i.e. like a balloon payment).

Of course, they may could could get their lender to write a letter that they didn’t qualify, but I’d make them work for it.  

"Proof of Funds w/ Cash offer or PreApproval Letter from Lender based on satisfactory credit, Income & Assets) Contact Listing Agt for Appt.

We had one that wanted 6 names on her mailbox & the surname from memory was at least 8 letters!!!

If the tenant still owes money to you, then send them a kindly worded demand letter to their last known address.

I have a letter of commitment for purchase of the existing house at 130k and a national builder that's wants the five remaining lots at 33k each.