If I understand correctly your siblings goals are to sell their rental properties, use the funds to purchase a primary residence they'll eventually move into, and limit their tax liability correct?

Your screening is limited to ONLY what RentRedi thinks should be part of the screening process, and rent payments...well, you will be reported to the IRS for the fees RentRedi charges..and RentRedi will not give you their W9 to write those off as an expense.

It was on the more limited side in general (for a few days' worth).

I've only had one listing transaction from my BP leads.Most are complete noobs or have limited REI experience with a rental or two.

This event is free but has very limited seating and we are limited to the first 50 to RSVP!

What is their federal lending limit?  

Most credit collection agencies are limited to sending demand letter for an initial fee of $200 to $240.

If you were limited in cash reserves atleast you'll have the HELOC as a 2nd or 3rd back up source of funds to weather storms.

Though Buildium has its limitations, its financial tracking is quite robust.

When faced with scenarios like this, it's tough to answer such a specific question with limited information.