@Richard PastorI would urge you to get a commitment from a lender on a heloc BEFORE going down this path.

Of course you can, it just may take you a bit to get there.

I've been doing a deep dive looking at cash on cash return for various down payments and expenses on properties with a mortgage.

For anyone who has experience with this, 1) is this a good route to take?

If this is financing for a stabilized property rate carries more importance but rate combined with origination fees, pre-payment penalty and term in which you intend on keeping the loan in place are all considerations which together should help in deciding the best financing option.

But it looks like a horrible deal. 

Total rent between the three is $3200/month.I have an adjustable 20 year mortgage with a balance of $100,000~ at 4.95% that is set to adjust in 2026.I also have a HELOC on that property at $180K~ with a 9.75% rate. 

Applicants can view properties without scheduling, after hours, and on weekends or holidays.However, the lack of human interaction does come with a price.

Yes, most large traditional lenders only focus on 1-4 units and other properties that fit into a box. 

Mike, My recommendation would be during due diligence for a potential purchase, ask for past 12 months of all utility bills, property taxes, and any other municipal requirements like rental permits, occupancy inspections etc.