You must establish a specific set of search criteria.  

It is always a gamble you take on any offer you accept.BUT -- to reduce your chances of the buyer not qualifying for a loan, ask to have the buyer cross-qualified by a lender you know, like and trust.

I have a fairly established rehabbing/wholesaling business (done about 115 deals since 2010), and am considering bringing on my best friend from college into the business with me to help me scale and start a Brokerage business.

Yes, you might get a quick hit from some national lender but you'll be better off in the long run establishing a relationship with a good local bank - one with real people who will get to know you personally and grow right along with you.

It's a gamble as some can be damaged but it's usually a good deal.2.

The question I was hoping to gain some advice/input on is how to establish my business partner's equity in the property.

At some point you will use a commercial lender and they are more likely to work with you with an established business.  

We'd love to spend more time with family, do more volunteer work, and establish a permaculture farm together -- and teach as many people as we can, as much as we know along the way! 

I would definitely be a bit nervous working with an out of state company myself...super important to do careful research to ensure they are legit and established like you said. 

We'd also like to meet with hard money lenders and bankers to establish local financing relationships.