What documents do they require, what credit scores do they allow, how do they verify previous rental history, etc.?

With 700+ credit you should be able to get mid to high 6s if you pay a couple points and do a 5 year pre payment penalty.

So if you have good credit and cash, it makes starting any type of business a lot easier. 

I used Hanscom credit union, which I hear a decent amount from other investors in MA.

I always thought I needed tons of cash or perfect credit to get started.

Perform the same task in each app to ensure a fair comparison.Load a property with pictures and details.Market that property.See what your marketing looks like from the public's perspective.Submit a fake application to see how easy the process is.Run a credit/screening report on yourself.Enter a maintenance request, assign a vendor, and attach a fake invoice.Enter charges to the tenant's ledger.Enter recurring charges and automatic late fees.Sign documents electronically.Run owner reports.After testing a few apps, one should clearly stand out.

I have the credit score and make a good monthly living but I have no cash save up but have 2 cash flowing rental properties with one of them having some equity.

Are anybody still doing second liens or a line of credit on investment properties?

Calling me a "newbie" would give me too much credit, but I do want to house hack when we move, and then look into rental properties if I manage to be a decent landlord.

They currently have under $1M in leverage on the assets but are looking to get a line of credit / portfolio loan to encumber these properties or other properties they acquire.