In my day our investors that were funding new origination's for fix and flippers in the bay area this was very passive.. 

Receipts for funds given?

they were in business 20 some years took in 100 of millions in due diligence fee's at 5 to 10k a piece.. there targets were newbie developers who had bigger complicated projects that no one would fund when you have little to no experience. 

We might like to spend more time there when the kids are done with school in seven years (work is flexible and we can work from pretty much anywhere.) 

They have used a hard money lender to renovate and are now out of funds.

They have some excellent teachers and excellent schools especially in the suburbs. 

That being said, assuming our next purchase is going to max out our DTI, should we prioritize purchasing the owner-occupied property first, and then look to unconventional funding/portfolio loan for the investment property?

.), and an idea of how you will fund a deal before making contact.

If we want to make an offer in the meantime, how do we show proof of funds and how soon do they expect the full payment.  

show all the states we fund investors in  and their product to hopefully help our Vendors sell more or BRRR more props with our help..