You may find value reading Dave's book "Total Money Makeover" --Heck, I'll buy it and send it to you, just message me your address.  :-)Also read: "The Millionaire Mind" by Thomas J Stanley... talks about how Millionaires handle money.

The startup had some bumps with M to M tenants and one apt. needing a makeover.

Does the seller really mean no business <full stop> or did he envision someone running a moderate traffic business (i.e. hair salon, tailor) or home-based auto-body shop in his front yard?   

I will point out that on a small build it may not be worth that money because the "test" they do is not a soil sample or boring of the land, it is a research into the property to determine if a laundry facility or auto body shop or some contaminate / polluting type of business or entity was once on that lot a long time ago.

In part because it is now a gorgeous home, and in part because the neighborhood is changing that much with new $400-500k homes going in all around us and similar row homes being flipped and sold for $200-$300k.So... using less than $20k out of our own pockets, we did theoretically already make over $100k in around 6 months time.

There is a "spread" that the lender will make over the 30 year treasury yield that corresponds to the amount of risk in the project for them.If I am you, I am asking what the "caps" are on the adjustment every year--that is--how high can the lender adjust the rate?

From from I saw they must make over 120K a year just to meet the debt to income ratio?

Don't just put a body in there to put a body in there, you wont have the time, energy or money to evict at this point.Take cost to remodel plus cash flow to the bank with your asking price, if you can get a pre approval to buy the property than present your offer with what is needed to spend on property.It took me a year to get the bank to take my offer, once a month I would stop by just to say high, they had other offers, but then they would go to the building find out what a disaster it was and either walk or change the offer, the bank always said no, why you ask, because not one of the offers came with a pre approval, unbelievable, cash talk BS walks.The Bank I received the loan from looked at the remodeling numbers than market value after completion, I took the banker on a tour of said property showed the my written plan and bingo, he says this is a great deal.

I know which are good/ bad from a renter's perspective and would be interested to know which are friendly to investors.Also, the school's student body grows larger each year. 2 year lag between incoming class and when they move off campus.

There are federal poverty guidelines that they must make over annually for you to even attempt a garnishment.