We are researching home equity loans, home equity lines of credit, and the possibility of refinancing our current mortgage to free up the cash needed to make those improvements and make the down payment on the multi-family unit. 

Venmo allows you to use a bank account or debit card for free (they'd charge 3% fee if using a credit card). 

Due to the nature of my career (I'm an economist with a tenure track job), I have fairly idle summers.

Credit low only due to card utilization.

It seems you are already on track with some of the avenues to find your first investment property. 

I’m in the philadelphia area and finally through some VERY hard work I was able to track down an interesting lead.

The approval is based on credit, cash flow of the property and loan to value.

A place for opportunities with high rent returns for relatively low purchase investments.This question assumes you have good enough credit, debt/income ratio, income, etc that getting the loan will not be an issue.  

He wants an upfront fee of $795 and he says it gets credited at closing.

I have cash and credit.