for us being friends, she said this is already a friendship discount, since she normally charges 25-35% for other clients (which I don't think she even has other clients, because she started her own company and used foreign investment money to flip places and pay back the investment capital + interest)Her current estimate of 100k is only her guesses, without really having anyone or any real contractor giving her a solid quote.

We will charge per unit for the ones that are submetered.

It is unlikely seller will give you 40% off knowing 220K is already discounted.I do not know what HOLDING COST-may be interest charge perhaps.

Check the pricing on Vrbo and Airbnb and get an idea of what people are charging.

I charge $55 per patch and sand so I advise that they do it beforehand, they usually do. 

What type of taxes are typically charged on rental properties in Springfield, Missouri?

This current condition is the only one you can charge for when they go to move out. 

Charging tenants for repairs probably wouldn't stand up in court but I know a lot of Landlords do it.

Do you think I can also charge them for the tub replacement itself?

All of the above sounds like nice work if you can get it :) But the layers of risk to a newbie investor are not in your favor and you didn't even tell us what interest rates the HML and PML will charge you.