different shoes different activities?

Hi ​@Chip, you've answered your question yourself - indeed it's done via assigning a specific Default Sport to  specific pair of shoes. However, as far as I know it's not possible to do that for Football, only for walking/running activity types (Run, Hike, Walk, Virtual Run, and Trail Run); and from what I see when trying to create a sample Football activity, it's not allowing to assign any gear even at that point.

Having said that, there's a pending feature request that should cover this - you might want to check it and possibly vote for it: