Strong work Mark. Unfortunately the Smartweed will spread, so just a few light-work options.
First, if you still have the DFD hire for help, then him walking around the clean bank with a backpack shouldn't be to bad. He could spot spray with Gylphate/surfactant combo on what will more likely pop up again. The bank looks very nice, and it's still wet. Pott's Feed Store in Emory has rye grass that pops up in 4-5 days if damp. It's around $35 for 50 pounds. There are feed stores around you, so you may get it closer too. It looks nice, and it will help hold the bank until the turf takes over.
Also, an easy way to clear areas is Navigate. It's not cheap, but spreading granular 2,4-D works well once it settles down. I've helped some lake dock owners that were infested with American Lotus. Navigate slowly killed them from the tubers, and the docks have stayed clean.
Spreading down wind and safety dress is needed, and this is what I use.
SOLO Chest Spreader. Also, most 3M masks and cheap plastic goggles work well if they fit the face. Cheap throw away nitrile gloves help too.
I hope this helps.
