FWIW, I'll share my experience with rebloomers. Love irises, so was seduced by the reblooming 'Immortality'. It is a lovely pure white iris, and does rebloom reliably in the fall ... but, to me, it just looks out of place then. I won't get rid of it, but I certainly wouldn't buy it again. I think I'd feel the same way about reblooming azaleas.

Not a shrub, but a vigorous vine, and I don't know if it could be pruned/trained to meet your needs, but my native honeysuckle, lonicera sempervirens, blooms in part shade from spring (flower buds are actually about to pop open any day now) until taken out by frost, all the while attracting butterflies, bees and hummingbirds.

Clethra alnifolia (summersweet) blooms in summer, even in shade, and I believe there are some compact cultivars.

Calycanthus floridus (Carolina allspice) is also tolerant of varying light levels and most have very fragrant flowers. My 'Athens' blooms with pale green flowers in May, repeating lightly throughout the season. Blooms are followed by interesting seed pods.

Itea Virginica (Virginia sweetspire) also blooms in shade, but only May-June; however, the brilliant autumn foliage of some varieties is wonderful (I have 'Henry's Garnet' - after the fall foliage color).

Dwarf hydrangea quercifolia (oakleaf hydrangea) is another that leafs out early, will bloom in the summer for about 6-8 weeks, then provide awesome foliage color in the fall.