Shelter is one of the basic human needs, hardwired way down in the lizard brainstem.You're showing up after years of allowing him to feed his innate tendency to believe that your place is his permanent home for many years, and at some point you're going to present him with the panic-inducing proposition that this is the end of his housing security -- you're not going to be renewing the lease.Ideally, he'll get over it.

The 1st deal is still ongoing, and I had to exercise my pledge agreement I had on Kevin’s entity as he still hadn’t sold or repaid me.

If you're wrong and prices keep going up or flatten out you can exercise your option.

But, the whole exercise now becomes: at what list price does this property make sense?

For example, the pros list for the desirable duplex may look something like this:Safe locationUpdated kitchenNice viewsLocation proximity to workWasher/dryer in unitDishwasherEtc.If you don't care to do the exercise above, then my short advice is to buy the duplex that you like. 

Tenant-buyer must exercise their option within 180 days.2.

I have a hypothetical question for the community about purchasing a 4-plex that has been zoned for 2 additional units.This is a hypothetical exercise to identify gaps and valuations not currently under consideration.Feedback is appreciated!

The owner is asking for 10K down and 900/month for 2 years, at which point I could exercise the option and purchase the property for 125K.

The tenant doesn't own anything until the option is exercised and they actually buy the property.Owner financing is the owner acting as the bank with a promissory note with the terms of payment (principal amount, interest rate, number of months).

Otherwise what was the point of the exercise. good luck.. consider posting the new calculations based on 650-700/ per unit to be conservative...