But if you plan to scale up, aren't you talking about $1mm to $2mm upfront cash to support your deals, prior to lenders? 

If the lender foreclosures wouldn’t it wipe out their lien?

Typically HELOCs have adjustable rates and if the banking climate changes I believe the lender can actually cancel them at their will.

I would start with the comparables in the area.

This is in sharp contrast to our properties near Santa Cruz, California, where we spend most of our time and energy.Californian's are known to be laid back and soft compared to east-coasters. 

What are some tools that people use to figure out what comparable homes/units are charging tenants for rent in an area you're interested in investing in?

If comparable units rent for $1,200 with the tenant paying the utilities, then $1,200 with utilities included is a pretty significant price reduction and it's unlikely the tenant will leave.

Medical/physician programs are typically best for primary or investment purchases..check in with @Joseph Chiofalo he is a national lender and refinance savant that's worked closely with me for over two decades.

Lenders may not qualify it, it's up to them.

Another suggestion someone gave me was being the bank and act as a private lender at 8% to 12% interest - you would need to vet the investor and project carefully and financial transactions are done through a title company.