I agree that DealCheck (or the BP calculator) does not provide enough tools or functionality to analyze those types of transactions (yet).But I would argue that it does a great job at analyzing more traditional buy & hold SFRs and multi-families, as well as flips and rehab projects. 

They refused to accept my terms and said I would need to put down 30% versus the traditional 80/20 with conventional terms.

However, we often facechallenges in sourcing suitable properties through traditional MLS listings.

Two of my units will be vacated in the next 2 months so this is a good time to consider this over my traditional 12 month leases again. 

Not your traditional subdivision.  

We have an added layer of stress compared to something turnkey in the traditional sense. 

I have used both Traditional (pre-tax) funds, Roth and HSA.

When you do a traditional 1031 exchange you have 45 day identification period, to provide a list of potential replacement properties and 180 days to close on a replacement.

That's not the topic of discussion - we're talking about saving INTEREST using a HELOC payoff strategy versus a traditional monthly payment strategy.

In many/most BRRRRs that is irrelevant because when the property is bought it is often not fanciable using traditional mortgages.