This longer life would negate some of the tax benefits that are afforded to owners of residential rental properties (due to the shorter depreciable life on those types of properties), and would most likely cause your rental income to be taxable more often then not, right?

If so, you need to have an agent's license or be part owner?

If potential owners can't get qualified financing then units dont sell and thus prices decrease without rental restrictions.

My fiance and I are the owners of the home for around 13 months.

Which is counter-intuitive, normally Fannie is more generous to owner occupants than she is to investors. 

In my original post I was trying to calculate how much to offer to a home owner to buy their house.

If they did the bank would not accept a big loss on the note but would want the owners to make them whole instead.So doing specific performance etc. can be a waste of time with a short seller.

If your goal is cash flow (in my opinion) you're better off trying to buy with owner financing (contract for deed - land contract, installment sale, mortgage wrap, promissory note with a first lien holder position on the trust deed for the seller (if they own it free and clear), or sub2.

It just bugs me that there are irresponsible management companies out there and I'm sure learning what not to do as a soon to be property owner.

If the house is actually valued at $500k why would the owners want to sell it for $300k?