Joyce you may recall that is how I found Ripley - stopping in at a shelter for a completely different reason! That is amazing!
As someone who has always owned two dogs at a time, I can tell you that I do understand your concern when introducing dog #2. It is only natural and of course you and Ginger have been a duo for quite some time now. I feel that all will work out just fine. You were wise to select a dog that looks like those she searches out for play. I think in the long run Ginger will thank you for giving her a little brother. That's exactly what I did - gave Bella a little brother! Our stories are so similar. :) Please do keep posting lots of pictures and stories about your two.
Oh, and don't be surprised if he attempts to mount Ginger at some point. Ripley did that with Bella in his first 15 minutes in my house! :o She simply sat down. :)