The article linked below recommends Viburnum prunifolium.

I found another Wisconsin site that recommends Cephalanthus occidentalis, button bush. Although this shrub gets much taller in southern areas, it apparently is much smaller in your area. It has very showy flowers.

Here is a link that might be useful: Johnson's nursery

There are small oak leaf hydrangeas that I think would do. The regular ones are enormous, but I have seen the dwarf ones in landscapes around here and they look nice with flowers on from spring til fall and they dry in winter. I have my regular (humongous) oak leaf hydrangea on a north facing wall which is loves. I don't know final size of the dwarf ones though.

You may want to research which plants are juglone sensitive, cause that stump will have tainted the surrounding ground if it was a big walnut tree.

Also, I like the japanese maple idea a lot, but in IL here, I have mixed hardiness. (I have 3) and any given winter I have tip dieback. Sometimes significant. But if you want to try, it would be way cool. Maybe if you were willing to winter protect?

After 3 years, the roots should have pretty well rotted, from the BW - I don't think it will pose a problem.

I don't know if it would be hardy for you, but I have seen a new Oakleaf hydrangea cultivar here - 'Little Honey'. It has, as suggested by the name, golden yellow leaves, some with a red tinge (very attractive, and I don't LIKE yellow-leaved plants as a rule!), and is supposed to stay under 4'-6' here, as I recall, so it may be too small, but there are other smaller Oakleaf hydrangeas that might do. They do have good fall colors, as well as the flowers.

There are native shrubs that have great fall colors - Iteas or Clethras - as well as attractive early to mid summer flowers. Both of these can sucker to form colonies, but I find the suckers easy enough to dig/pull out in the spring - either pot them up to give away or plant elsewhere, or toss them in the compost pile.

A variegated evergreen might be attractive - flowers not needed then. How about a holly - you can prune it easily for size if it starts to outgrow the space? Most of the variegated ones I know of are males, but there may be females as well, so you could have berries.

There are always the winter colors of red- or yellow-twig dogwoods, although they may be less interesting in the summers, or in flower.

If clematis grows in your area, you could grow one (or more) through whatever shrub you planted, and have the summer interest from the clematis flowers, instead of a plain green plant. It could confound your visitors, as the flowers and plant would have a mismatch! Clematis grows lightly enough that it won't strangle or smother the shrub.