Especially since you haven't nailed down the rents and the ARV.You should use tools like Rentometer and others to get rents for an area.

I'd say first thing is to try to nail down a budget and then a couple neighborhoods.

Andreas nailed it.

Walls had extensive nail damage/patching, walls were in bad need of painting despite providing paint to tenant multiple times during tenancy.

On a first deal I think that can be challenging to nail and sounds like you did a good job?

Make sure you get esstopal letters before purchase to nail down the details of their lease.Why terminate.

Sounds like @Adam Menconi and @Bill Bockwoldt are great resources so I will do my prep work.Re the use permit, you hit the nail on the head.

There are plenty of lenders out there that don't have a cap on the number of properties owned.  

A win for the investor (which can only be determined by finding out what their needs are for being a part of this and nailing it), a win for you (purchasing an asset using someone else's money), and a win for the tenants you are housing (making sure you take care of each and every tenant ethically and with respect). 

@Jason Chen I think you nailed the sentiment of the other posters. 2011-2015 Duplex's in solid neighborhoods could be found in the $50k range, particularly in the midsize cities of the midwest.