Learn how to to screen and select a quality property manager that won't cheat you or mismanage your property (they do exist).

I am also negotiating a "Subject to" property with one of my existing clients.If you can get legs on the PM company (get to 200 to 300 units quickly), you should be able to have enough cash flow to be able to fund your purchases.If I were to do anything over, I would have quit my engineering job sooner and started in property management.  

I'd also appreciate any recommendations on where I may be able to find furnished properties, existing Airbnbs, etc. for sale.

I am interested in adding to my STR portfolio and helping my family increase the revenue of their existing investments as well!

Just keep in mind you are paying a significant premium for that peace of mind. 

For both tenant and landlord peace of mind, the property had an extensive video surveillance and security DVR system already installed by the prior owner, which covers outdoor areas and indoor common areas and records 24/7/365, as well as sensors for excess dB noise levels.

Yes Helocs using bank statements absolutely do exist.

The tenant screening process seems non-existent, and they have no problem blatantly lying to you (my final straw before finding new management this month). 

Another option is to find a nice existing home and do a remodel to make it "yours". 

I have formed opinions on questions like:Do new construction homes or older/existing homes appreciate more?