The reason sellers cannot sell these properties through the traditional market is often due to certain issues, and 98% of the time, these issues are not beneficial to you as a buyer.

This is one of the biggest insulation issues second only to the attic.

They are paying for some repairs now after I've had several issues and a brand new tenant moved out, but I'm still paying a mortgage without any rent coming in during those months. 

Why are you entering a hospitality business to automate your (im)personal responses when guests have an issue?

You are micro-analyzing the minutia of each offering, but that's not really the issue.

The interior was outdated, the landscaping was overgrown, and several deferred maintenance issues were apparent.

I've been teetering around the idea of house hacking once I am done with college, but a big issue I have come across when speaking to a mortgage broker is the fact that I need to prove 2x of the mortgage in monthly income.

Lender A misses this or doesn't have this knowledge and then tells you a week before closing that your rate is changing because the program they quoted wont work once the issue is caught. 

The foundation was already approved, permitted and finaled years ago for a 3400 sf house, and its solid and I won't be building directly on the overhang edge; but rather back away from the edge a few feet to prevent any load issues all the weight will be on the longer sides of the existing footing.

Usually an issue if older door is salvaged and new locks are installed that don't quite match up with the old door strike plate location.