The Red Owl Store is now a Cub Foods. (The building was added on too and includes another larger building and two small business locations.)
The smaller locations have at least had the following businesses: RadioShack, Hallmark, All4Kids, and Sweet Dreams Mattresses.
The other larger building that was added on was used by KMART and is now used by Runnings.

The small restaurant on the left corner is the Country Kitchen. It is no longer the Country Kitchen, but has been used for other restaurants. The current restaurant in the building is the Pancho Villa Mexican Restaurant.

The building on the right bottom corner is Kentucky Fried Chicken. I am not sure if the same building is there but Kentucky Fried Chicken is still in that exact location.

Addresses for the buildings:
300 7th Street West, Monticello, MN. (Runnings) - former KMART
220 7th Street West, Monticello, MN. (All4Kids) - former Hallmark
216 7th Street West, Monticello, MN. (Cub Foods) - former Red Owl
100 7th Street West, Monticello, MN. (Pancho Villa) - former Country Kitchen and others
701 Pine Street Monticello, MN. (Kentucky Fried Chicken)