Once you start "telling dad" other people seem to find all sorts of things you are doing wrong.

I'm not in a position to do this yet as I have not developed any sort of network yet but I WILL be able to one day and I simply love this idea it sounds like there is no way to lose.

Some commercial lenders may let you do this via them placing a second mortgage on the duplex, but I've not attempted this so not sure what sort of appetite there is for this kind of loan.If you're going with a commercial lender, just ask them what they can do and they'll tell you. 

All you want to confirm is whether the deal is good and your attorney can sort that once you have a contract signed.This is a simple solution I've done it hundreds of times.

If you want scale, you will eventually move into the larger units, but there is nothing wrong with getting started in the 2-4 unit space. 

Two buildings on one lot...if you rent out the larger building, you could live for free!!

Melvindale is a sort of hit or miss. 

Should the two tenants make some sort of agreement together?  

I have seen for larger projects developers or flippers bus in crews from less busy states to get high quality contractors looking for work.Larger flippers or ground up development companies can build for say 85 per sq ft where smaller investor with 1 property might be 120 a foot.

The contractors will support their returning customers or larger jobs more intensly then smaller low margin jobs with a new client.