I had a tenant that was imagining noises from the upstairs tenants and would not put up with normal noise such as walking, doors closing etc at reasonable hours. 

Just the Condenser for $17K sounds like you paid five times a normal cost with installation.

This is where expert due diligence comes in, so as to avoid gambling away your business.Expert due diligence is crucial when it comes to business transactions.

Normally our issues revolve around changing a price.  

(Higher than normal rent.) and I will give you the option to buy the property in 5 years for selling price minus x, maybe minus some of Y. 

Normally, the better route is to rehab one unit at a time so 1. you have some income coming in during the rehab.2.

That question will require an essay to answer every part of your question :) With stocks, you mostly gamble on appreciation.

I have already ran all utilities from my original rehab budget but need about 30k more to finish.Now im 22 and really took the gamble putting most of my money into the original deal so savings isn't really an option.

One person booked at the normal rate instead of what we quoted and the other somehow had a pet fee attached which we still don’t understand since we do not have that as an option.  

My largest goal has been to get my "semi" passive to 10-12k mth to exceed my family's 8-10k/mth normal spending.