I chose dwarf crab apples that have tiny apples which birds love. The first time I saw cedar waxwings was one crabs along the driveway to the bank parking lot but the bank decided the trees were too messy and replaced them. Our birds seem to do a good job cleaning up. The trees hold the little apples all winter so the fruit is enjoyed by migrating spring birds. One is a weeping crab in the middle of a perennial bed. The other is a dark leafed variety by itself in the laws. I'm in zone 5. The perennial bed also has: hummingbird summersweet shrub, a pink azalea and a mayflower viburnum so I have a variety of pinks flowering in May. My first viburnum is beautiful, tall vase shaped but grew too big for its location next to the house so it was moved to my future shrub garden. For a low shrub, see is spreading cotoneaster is ok in semi-shade. Again, it is enjoyed by the birds and is appropriate next to our short walkway to a small kitchen porch.

Downy Hawthorn (Crataegus mollis)?
American Mountain Ash?

For the larger area, Pagoda dogwood, Cornus alternifolia, has flowers (though not like the standard dogwood tree), berries that the birds love, and pale yellow to peachy fall colors.

I like both the crabapple and Hawthorn if you check to be sure your selections are disease resistant.

For the 10'x10' space, only a few of the weeping trees will stay in such a small space, so you might want to consider a shrub instead, since you won't want the tree growing out over the stairs. When you say semishade, does this mean dappled shade for much of the day or full sun for only part of the day? Is the shade bright such as caused by a low building with no trees nearby or dark such as when the plant will be sandwiched between overhanging dense trees? The quality of the light will effect what will grow there. Are there windows you don't want blocked and so will influence the height of the plant? Often having a photo will help me understand the situation if you can add one.