Looks very nice, great idea and battle choice. I know this battle well and have walked the field many times.
I second comments about cavalry being largely limited to recon/raiding units in the ACW. Google "Elon Farnsworth and Gettysburg" if you want to learn about how cavalry assaults on infantry positions turned out in the ACW.
Anyway sounds like a great project. Would love to help you playtest. Go, go, go.