I don't have good 'rule of thumbs' for you there on a per unit (for instance per foot) cost. 

Pick up 10x Rule by Grant Cardone and aim higher young man!

One thing I like to do in abq is if I’m purchasing multi units in rougher parts of town make sure I’m getting a good deal on purchase price (usually my numbers are around 1.3-1.5% on the ‘2% rule’ if you’re familiar with that so I make sure I’m getting solid cash flow.

@David EpsteinThe IRS has consistently ruled in favor of NYC coops for 1031 exchanges.https://apiexchange.com/new-york-cooperatives/

What we did on one of these was to do the project after we learned that they were already utilizing the bedroom as a bedroom anyways (against the rules) - we didn't increase rent right away but gave them a year at current rent, and gave them visibility into what we thought market rent was going to be after some time and the option to stay at the increase... 

Also, the number 1 rule to wholesaling, in my opinion, really should be “try not to wholesale”.

Hi BP,I am aware of the 2% Rule when it comes to Real Estate investing.

If things get testy, I consider myself  to be in the manager (or parent) role: "them's the rules, you agreed to follow them, here's what happens next." 

You could say the dog is not allowed inside the house, and they have to clean up after the dog every week, but be prepared for them to break that rule pretty much every day starting on day 1.As an aside, in some areas you could have trouble if you disallow dogs. 

Run away from this deal stop trying to justify wasting money.