I got a very lucrative multi-day booking this fall, and then tried to cancel just a couple of weeks later claiming I want except her service dog which wasn't true.

@Robel Nessro We've worked with many service men and women using this strategy.

He even provides a service to help you find the right one.

At that time we could renovate the ground floor apartment and potentially turn it into (2) apartments for a total of (5).My questions come down to how do we deal with the existing 40k mortgage, whether we can make it work so her parents aren't paying much in rent, if anything at all, and whether or not we set up any legal entity, like a trust to help the legal situation of paying off her sister down the road. 

Customer Service and SupportIs there a dedicated business banker you can reach out to?

It's important to keep in mind that everyone you hire is providing you a service - no one is guaranteeing you any outcome.

If the property can service the debt at 90% leverage between a senior 1st and the seller second, you're looking at a good investment!

To clarify for those reading the company is Prime Corporate Services out of Utah.

Quote from @Josh Jung: surprised you haven't heard of RBP. it's like a mix of services you can offer to your tenants like renters insurance, virtual concierge, etc So the property manager/landlord pays for their renters insurance, and filters?  

This is what happens when owners go with the cheapest PMC services they find, yet have no clue how the services actually work.- The new PMC you want to hire will have to increase your Placement Fee, so they can offer a commission to an agent that brings then a tenant.