BRRRR with investor who desires equity?

[Cody Gordon]

Hi there, I'm a newer investor working with a funder who I'm trying to convince to do hard money / short term loan on a deal with me, however they are positioned as an investor themselves and are unfamiliar with BRRRR or even hard money. They are a wealthy foreign national and have only done simple cash deals for rentals with minor/no rehab, leaving it at that as they aren't able to get favorable rates from U.S. lenders.

I'm wondering if there is a scenario where a lender would refi (ideally with a conventional product) using my credit, while also allowing this foreign investor to retain some equity? Similarly, is there a way for someone to pay down a % of principal on someone else's mortgage and legally (confidently) be assigned equity? Or would it an agreement not supported by the financial institution who owns the mortgage until the owner can change the deed type to tenancy in common when the mortgage is completely paid off (thus being low confidence for the person "unofficially" paying into equity)? 

Also, if this investor fronted the money for the purchase / rehab but it wasn't technically a loan, per se, would the lender look at it as such regardless as it would be paid back, thus requiring the 6 month waiting period?

Thank you!