I am currently a credit analyst for a bank (I analyze ag and commercial real estate), but I need something I am more passionate about.

We do however have a conservative $150k equity in our primary residence as well as access to other forms of credit to get the job done if needed. 

I also require credit checks. 

ThanksJimmyGo sit down with a loan officer at a local bank or credit union.

Probably not likely unless you have a lot of cash in that checking account.From experience with my business (not real estate) no lender will entertain a line of credit without substantial cash reserves or very strong history to show.Probably better off trying to open a bunch of credit cards at the same time and use those for the repairs.

The other partner is securing the loan with their credit. 

I not only help prevent a foreclosure which ruins your credit, I increase their credit by paying off their mortgage of a house they (more often than not) no longer want.

Credit check revealed excellent credit scores, but also an incredibly high debt-income ratio; otherwise, no delinquencies or criminal background.

I have a credit score of 697 but no US income other than regular child support.

Taking on $50K in credit card debt to go through a guru course isn't the same thing as a 30 year fixed rate mortgage of $100K on an income producing (hopefully, anyway) duplex.