A good starting point will be to pair with a with nationwide lender (if not all cash), check in with @Joseph Chiofalo for financing without a US credit score. 

I assume this allow them to come to closing with less cash down. 

Currently, I find myself in a situation where a significant sum of my cash is held up due to complications between these entities.

Apparently our DTI is too high for the HELOC so we can do a cash out refi but that is less desirable because it means we cannot then get the loan for the rental property despite having 25% down.

If I do find something, it is usually because it is priced according to condition, but once you value add and bring it up, you've now spent more cash. 

We have 5 Duplexes that we’re looking to cash out refi.

I am looking to purchase a parcel of land in Michigan and plan on using cash for the purchase.

YES, you can still achieve cash flows of 7% to 10% in the single-family residential (SFR) sector.If you want to learn more about these opportunities, don't hesitate to reach out.

I get texts/postcards/calls offering me cash for the house a lot, but I don’t want to sell the whole thing outright, I want to retain my ownership and investment and build a property empire with someone who wants to invest - and I’m totally okay with full involvement or silent partnership. 

The plan here is to have a local (RV Certified) tiny home builder do the marketing to attract buyers that want to buy their tiny homes (cash or 25 year financing) and live in this park, until there are 44 pads occupied by tenant-owned tiny homes, paying $750/mo lot rent, on 1 year leases.