Washing machine hook up but not to a drain, A/C condensate not routed to outside but in the walls (that was fun), electrical issues that were to be "repaired" but were not actually.

I have also received different feedback on how many heads maximum you can use for one condenser. 

If central air is added and tenants like to keep their home very cold - say below 70 - the walls with sweat with condensation if it is very hot outside. 

Just as some background: I'm a 20 year old college student, I was lucky enough to get lots of scholarships (so I'm actually paid to go here), and I also have some part time jobs that have allowed me to save up some money that I'd like to invest into real estate.Because I'm in a condensed college town, most of the real estate investing around here is actually very profitable since a majority of students live off-campus, and even the most expensive of rents are cheaper than dorm living.

The HVAC company inspected it and said no leaks were detected from the condensing line.

The 2nd hand market for AC condensers is limited.   

The house has ducts for a heater but does not have a condenser and coil.

When you're paying off so much quicker, it's less about interest rate and more about interest cost over that condensed timeline. 

A few months ago, a neighbor told me that there were a few A/C condenser units stolen in the area.

I'll save you the hassle of exploring markets and information as I have it all condensed into one form for you with markets you didn't even know were cash cows.