This is a land liquidation sale.

I can second Normandy, as being a broker, they're a lender that I utilize and will do owner builder loans, but it depends on how much flexibility you need, b/c doing it in the steps that you've mentioned, unless you're very liquid, is not an easy task. 

The reason I was thinking about this is it would effectively reduce monthly payments about $300 which we would then just add to our savings rate for investing, and then also reduce DTI from about 25% to 22% (not sure if the DTI reduction would be a huge benefit when going to refinance with the bank).Or....Do I take the money, leave it in our savings account and just use it to fund the BRRRR(s), and have the capability of having true liquidity and then re-fiance out once we are rented?

Look for any new construction that may drive your rental price down, account for regular maintenance and upkeep, and be sure to have a sufficient amount of liquid assets available at all times for if and when something needs repairs.

It's only the time restriction to purchase and liquidity. 

The estate holder is expecting a cash offer but i can't deliver unfortunately because my partner isn't liquid for quite that amount. 

I would sacrifice yield, liquidity, and appreciation for low risk, non-leveraged, long term, investments with a proven track record.

We were outbid by a significant margin, and while the winning bidder was able to make it profitable, the profits were only a small fraction of what they anticipated, and the 3 year investment in 2009 wasn’t liquidated until 2018.

I am wanting to scale up my access to liquid funds, and currently exploring some creative financing options with what I have already. 

Maybe you're curious about what third party reports are needed or net worth and liquidity requirements.