Turns out their total monthly income is too low ($600 shy of 2 month's rent -- we require it to be at least 3 months). 

Maintenance fees and other costs have been very low as well. 

Can we ride on our credit for some of the ownership or would we need to put in $$ for the financing, too?

You have everything from low end inner city properties to rural properties and a ton of small towns in between.

If it gets 3 hits in 10 hours, it's too low.

Good Sponsors should have a portfolio of properties in different regions, and usually select properties rated Class-A—high quality, newer buildings with top amenities and low vacancy rates.    

. - credit score is above 800.Any guidance on above options or ideas on other financing scenarios would be greatly appreciated.Thanks so much!

@Spencer Elliott- 1) any chance you can leverage  any other properties  2) keep trying the local / smaller  banks and  credit unions for the builder to get  approved  3)  have you  tried  " builders  capital " ?

Not everybody is cutout for sales, and its a very low barrier for entry. 

We used a local credit union a few years ago to refi many of ours using conforming loans.