John, I think you're on to something. (I'm secretly jealous that you have all the GC skills because that's what steers me away from tackling projects like this, ha ha.) Your plan to be there yourself for a while and have your guy stay afterwards completing the work is a great idea. When you're there in person you'll really get a flavor for the neighborhood and the town as well as the quality of the subs you plan to hire, etc...
I admire this plan. In fact, I think I looked at this deal myself a few weeks back. Not 100% sure but it sounds familiar. I have no experience with mixed-use (never leased a bar for example), so it wasn't my cup of tea.
As far as St. Louis itself, I believe there are pockets of rehab and growth happening as we speak. The goal is to place your properties in the path of that rehab and growth which it seems like you understand and have done with this first deal. Well done, my friend. I am rooting for your St. Louis success!