Went into homes that were for sale and pitched renting to us so that they can take advantage of positive cash flow and paying down a few thousand more in principal.

Getting familiar with properties in your area and what a good building is vs a bad building is a huge advantage when you go to make your purchase.

I would sell it even with its prop 13 advantage.  

The only benefit to waiting would be if you didnt know where exactly you wanted to buy in/around Nashville, as well as taking advantage of lower down payment options that you can get for a primary residence - seems like thats not an issue though if you plan on putting 20% down anyways.

Like others have suggested, there might be panic selling to take advantage of or RE markets that may be hit with a financial domino effect, perhaps ones that are heavily dependant on tourism, auto industry or energy.

I heard "whenever you want" on a podcast, but I think the guest had a track record and a good relationship with a smaller bank.It seems like commercial doesnt have any advantage over residential from a refi timeline then.

The advantages such as being able to collect commissions on your purchase, access to the MLS and control over the offers you make far out way the disclosures@Abel Curiel  Next time you are in the area you need to try other BBQ places as Salt Lick is very pedestrian BBQ for us. 

Use it and its users to their full advantage

To what extent will the parties be free to carry on other businesses - while the joint venture subsists- if one party pulls outIs it intended that spouses/partners should also be shareholders, to allow for tax advantages from a broader split of dividends?

Hard Money will look out for you by looking out for themselves and provided extra checks and balances in due diligence.The other advantage of Hard Money is the reliability and availability.