Also we would make provisions that would enable my mother to call a portion of the loan due at one time to cover her retirement/expense, i.e. $50,000 in any 1 year period.

This enables you to take maybe 2%-3% back off the sale.

obviously depends on goals, but I would suggest the mortgage, as leveraging the investment will bump up your ROI and enable you to use excess cash to buy more

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He liked the concept which enabled me to complete the purchase. 

This right enables the Service to redeem the real property from the party who purchased it at the foreclosure sale, and then sell it.

You have zero control over the investment and hopefully will make good choices that will enable your investment to grow over time.

Then your holding costs will kill you and you wont be able to sell the property or even rent it out to come close to covering the monthly liability.In the rental game rents will shift but generally you are able to keep everything afloat. 

This has been long-standing and he seems like an enabler.

With the recent crash, it was typical for many of the whiners (people now currently losing their homes cuz they weren't qualified to begin with), to do the following:1) Lie about income, enabled by NINA, Stated Income and Assets, which was not an invitation to LIE, but to avoid excessive paperwork and to save time, what a joke,2) Lie about occupancy, stating they were owner occupants when they had no intention of occupying the home,3) Bill already mentioned, a smoke-screen of actual debts,and the list goes on and on...just agreeing with Bill, when does it stop?