@Andrew Mercer its highly unlikely that you will be able to add another unit so before you start anything research with the local code enforcement office to check if there are occupancy permits for the existing 3 units and if a fourth can be added.

Do not hold the unit for anybody...... if they want it that bad they are going to have to sign the lease, pay the deposit, first month rent etc etc etc, and just have to suck it up having 2 places rented at the same timeOnly other option, is a non-refundable deposit of one months rent.... so when they bail at the last minute, you aren't out that months rent.....Otherwise....no way...... why would you want to lose $$ to hold it for someone that has zero commitment to actually following up on their end of the deal?

But rarely)  This tells me all I need to know - that I was under the wrong impression about what the lender would require regarding using the existing rents to off set the debt.

You definitely took a good first step by finding BP and committing to learning. 

I always suggest to people to set up MLS / Redfin alerts on all the properties in their area and commit 20-30 minutes a day to going through them. 

The interest you save is great and the mortgage balance will accelerate downward faster.So now when that is arranged and recorded - there are a number of things you can do next - refinance - put the seller first in second place - you get cash -- when you are ready to sell you can take some cash, do a wrap on your interest free mortgage and your existing mortgage and charge interest on the money you owe (it don't get no better than that - the yield is off the chart).

I'm mostly concerned about what information i should receive before i commit to buying..

I am looking for 80-100k to rehab then refinance in B to C+ neighborhoods (If that exists there).

On this particular deal, there is plenty of parking and there is also a lot of raw land behind the existing structure.

We HAVE had things move quickly from city officials getting behind us, but that was with clear discussions and firm commitments.