Will lotrimin (clotrimazole) af-jock itch work for the feet?

Yes. That should be fine. Spray powders will work best if you need medication between the toes.
It can. Athlete's foot and jock itch are caused by fungal infections of skin. Keeping the area clean and dry is important. Any antifungal can work. If it doesn't get better see a clinician.

Related Questions

Jock itch/athletes foot/ringworm - can they all use anti-fungals like lotrimin (clotrimazole) af?

All are similar. Fungal infections, based on appearance or location. Those are the common names for the infections that are otherwise pretty much the same. Read more...
Yes. They are all fungus and hence can all be treated with an antifungal. I woul advise washing hands though prior to applying the medication on the different body parts. Read more...