This would help you confirm where the boundary is, and what you own and do not own.

Based on your fact pattern (was a personal residence first and then a rental, not vice versa) I think you might be looking better.

Line of credit costs vs amount in taxes paid vs strategy for property...etc...lots of personal factors that go into this that only you can answer.

I use it for my personal portfolio as well.

I personally don't want to use them again mainly because of the lack of communication 

My own STR is an example. 

Additionally, I’m unclear on how their ARV analysis is conducted since most properties can be found on Redfin or Zillow — does it involve an in-person visit, or is it purely data-driven using comps and suggested repairs?

I currently own 1 properties that im living in(single family home).

Some people who own homes free and clear simply leave them vacant 

You can wait for the tenants to move out on their own or allow them to move into a newly renovated unit at a temporarily discounted rate.