For example, I know that Lima One will waive a property's seasoning period if you use them for both the initial hard money loan and the longer-term DSCR loan.

I was considering a 50/50 partnership minus any money invested into the intial purchase or for renovations. 

Personal financing.

I know that I stand to make more money per renovation by just paying for the work, but I'm attracted to the idea of partnering with him for a few reasons.

The reason for selling is because the home has been a money pit (major tenant damage) and a revolving door (tenants leaving).

The most important thing to a seller is trust, ie trusting you w/ their personal credit, trusting that you know how to execute, etc. 2nd most important thing is understanding the nuances of how to structure the deal. 3rd thing is to have a great attorney who knows how to bring it all together. 

Another thing to consider is that large homes in my area are expensive so we will most likely not have a lot of money after the sale to rehab kitchens, bathrooms, and more from scratch.

Do you personally use them?

Use other people's money always. 

with self-employment money before you can buy a house. that  'm not sure about Dallas, but here in Colorado Springs and Denver where we work, the markets are kind of flat right now, so waiting a little bit to buy probably wouldn't change what you can buy too much.