@Justin McElroy  I think most lenders who will be financing construction costs along with the purchase will need contractor bids as part of the loan application, and you may need approved building permits before closing. 

Simply non-renewal (or if the law permits, monthly increases of their rent is a passive-aggressive way to invite them to leave). 

To share some numbers on how many projects are being submitted with multiple units... see below data on the permit applications for City of San Diego, which is a combo of public data + our analysis on text fields describing the projects (to extract things like unit counts... it's directional, not perfect data).

Wholesalers should adhere to industry standards and regulations, including obtaining the necessary licenses and permits, and disclose any conflicts of interest that may arise during the transaction.Overall, real estate wholesaling can be ethical if conducted with transparency, honesty, and integrity.

The first deal is the hardest, there are learning curves in establishing and working with contractors, pulling permits, and other things you may not think of so I would start connecting with people now and get your plan in place. 

By the time I was done I had spent 160k total (again including all commissions, permits, professional fees etc).

Baltimore County requires a permit and inspection for each new gas appliance you hookup as opposed to electric where you just plug it in (assuming, again the electric is already in place); no permit or inspection required.Gas in rentals, at least in Baltimore County and maybe in general, just doesn't seem to be worth it.Just some food for thought...

She costs $150 for initially getting the permit/license for my rental.

Also, check with zoning and code compliance to make sure this is a permitted legal duplex.

Everything about this basement apartment seems to be up to code, but I guess the previous owner didn't get any permits.