I would say you should start along the lines of something like that.

No need to screw them into window.https://www.amazon.com/dp/B00KKUBENW/ref=sxr_rr_xs...https://www.amazon.com/Prime-Line-Products-9809-Sl...

I currently have a single family home (4 bed 21/2 bath) and the first part of the house hacking strategy would be to rent this house out and then go and purchase a multifamily property to live rent free in and therefore save up more cash.

Factors include: neighborhood, size, amenities, school districts, age of home, SF, number of beds/baths, and all kinds of other features that may be unique to your area (pools in Florida, for example). 

I'm not familiar with those on-line programs, but if I were you, I would put the inquiry to them.

I can't remember the exact formula, but it is something along the lines of 70% of after rehab value - repair cost.

If you have a significant amount of equity in your home and you need cash, have you considered a home equity line of credit? 

It is under warranty but after several visits the contractor is blaming the existing pipework (the 'line set' and drain line) and wants to charge me to replace the line set ($500).

You are on a fine line as a Realtor and marketing homes where you are making a profit instead of a commission.

ArdoIt seems you might have a line of communication with the squatter.