I think you have to do what you feel is good for you and it sounds like your very stable now.. maybe you concentrate on snowballing one property and a time and get those paid for thats when you really start to feel the cash flow when you limit or retire your debt.

Owner is retiring.

My plan is to hold the place long-term and use it to help gain a stable income during retirement. 

I am looking to invest in the future for additional income for retirement and to help build something that I can past to my son.

The man currently living there is a retired wheelchair bound vet who always pays on time and so they have never felt right raising the rent as hes only living on his Army paycheck.House 3. rents for $800/m the loan will cost me $14,000 as a down payment and $6,000 closing costs, and should cash flow approx $225/m after mortgage payment are made.House 4. 

At the end of the day to combat that the rehabber hired retired cops who were on site to check ID of all the workers and that really cut down the theft..

I would be more concerned with where the title to mobile home was - was it retire and put on the property or is it still personal propertyThere is nothing you can do to make it compliant, if the loan has been current for 12 months then you have ability to repay because they have consistent pay history

This is especially true if the property requires significant upkeep or if the heirs live far away.Owners of Distressed PropertiesSellers who own homes in poor condition and can't afford the necessary repairs may prefer to sell as-is rather than invest time and money into renovations.Landlords with Problematic TenantsLandlords who have been dealing with problematic tenants, frequent vacancies, or costly property damage might want to offload the property quickly to cut their losses and avoid further hassles.Owners Facing Major Life ChangesSignificant life changes, such as health issues, retirement, or downsizing, can motivate people to sell their property quickly.

Didn't you market a number of funds claiming they were "safe for retirement?"

Optimally liquid reserves but often to include retirement accounts or other investment account statements