These kinds of loans do not need to adhere to Fannie Mae standards and can have terms that may be a little more flexible.

Which I don't want to do because then I lose all the flexibility I love about the HELOC to begin with.On the subject of the large minimum monthly payment, it screwed up my debt-to-income ratio and that was one of the factors that blocked me from getting the refi I'd had planned. 

I'd be aiming to have maximum longterm flexibility--rent the whole place for events while we travel, rent the lower level for a nightly STR when it suits us, or turn 1-2 of the levels into a LTR later on if I get sick of the STR gig.

Flexibility is a great attribute of success and it definitely paid off in this deal.  

@Carson Belknap in general, very large lenders just aren't flexible enough for us.

I will say that working with auction stuff you need to be flexible.

My plan is flexible and is open for modifications as I progress with my life.

The only other option is non-agency aka subprime, there is more flexibility on the LTV and income as you can do a No Ratio or Asset Depletion or Bank Statements deposits or DSC (debt service coverage)

I presume my landlord understands some tenants may have uncertain future schedules and want the pay-as-you-go flexibility.

Short answer: There's not much of a difference unless you have a separate entity holding the properties.Longer answer: There is some additional flexibility in how to structure a commercial line of credit.