I have found the easiest lawsuit to win is the one that never sees the light of day, and it's contracts that will see to that.

The EASIEST solution is to just make a per room rental rate that is all inclusive (internet, electricity, water, gas, trash, pool, landscaping, whatever).

Those rooms are the easiest to rent.

Giving them a gift would be effective in the beginning, then it would lose its effectiveness.    

You will have a hard time renting to quality tenants with the issues you are reporting so it will be easiest to do empty.  

It sounds like you are house hacking and living in one unit while renting out the rest which should be the easiest to self manage.  

I kept hearing things on the bigger pockets podcasts about how the money is the easiest part of the deal but didn't truly believe it until I went to a new gym with my girlfriend and met the owner. 

What is the easiest way to get pre-approved?

Meaning, you will be required to have 25% downpayment for the purchase of the property.Now, keep in mind that FHA allows you to GIFT money to a friend....so if you want to gift your friend money for the downpayment, but not be on the mortgage, this will allow your friend to use 3.5% down and it won't affect you as described in #1 above. 

You can pay in installments, or, give her a financial gift equivalent to that amount of rent; you could even give it to her over time.