Just to update ...
I emailed a SunTrust servicer & she confirmed that the "non-borrowing" spouse's income/debt/credit does not matter as long as the borrower's score is high enough to support the mortgage on their own.
I also found out that the down payment assistance programs are up and running here, so we 'might' qualify for up to $7,500 that doesn't need to be paid back!
I'm officially excited.
Thanks, everyone!