Deciduous means the leaves fall off over the winter. Evergreen means the leaves stay on, to fall after a year or more, and be replaced with new leaves - so evergreen doesn't mean that the leaves never fall, only that they don't all fall at one time. Evergreens come in two forms; conifers, meaning the tree makes cones for its seeds, taking in most of the firs, pines, etc., or broadleaf, which includes such as hollies, magnolias, etc.. And semi-evergreen means that in some climates, the tree looses all or most of its leaves, and in others, keeps its leaves over the winter. And now that you have been given more information than you asked for, may I suggest that you go to the arboretum and look at their trees, as well as asking around in your neighborhood when you see a tree you like? That way, you will have a good idea if you like the looks of the various trees that are suggested. You can also go to Google Images, and see photos, but it's not the same as seeing the real thing. Also, looking in good gardening books, especially regional ones, will help you decide what does well in Chicago and what you like the looks of. That said, you will be limited by what is available at your local nurseries, which I can't help with at all! As far as trees that meet your criteria, may I first ask how long you see yourself staying in the house? If you will be there for a long time, then the tree choice might be different than if you only plan on being there for a few years. Many of the smaller, flowering trees only live for a relatively short time, a maximum of 50-60 years, and more likely 20-30 years. So you might think about how you would remove the tree, if you were staying and it were a shorter-lived one. Otherwise, you can let the then-owner worry about it. The trees I would suggest, off the top of my head are, in no particular order: redbud, which has a purple-leaved form 'Forest Pansy'; dogwood, which comes in white flowered and pink/red, as well as several species and a white/green variegated form; serviceberry or Amelanchier; Japanese maple 'Bloodgood' with purple leaves, although it might not like the wind or cold, so may not be hardy; some of the hawthorns, although the thorns might be a problem; Carolina silverbell, might not be hardy; hollies, various species, evergreen, although the thorny leaves might be a problem; various junipers, coniferous evergreens, select for mature height, and shape, as they can be dwarves at 3' or giants at 60' in 20 years; Arborvita or thuja, the same as junipers; various magnolia species, broadleaf evergreen or deciduous, choose for mature size; various crabapples, may be disease prone in your area; various spruce cultivars, coniferous evergreens, selected for size at maturity and shape; various Hinoki cypress, coniferous evergreens, selected for mature size, shape and color; mountain ash, various species; lilacs, various; blackhaw viburnum, although may be slower than wanted; various other selected viburnums, same applies; witch hazels, may need too much shade; possibly some of the rhododendrons may be hardy enough, most are broadleaf evergreens. I would avoid the flowering pears and cherries - they are pretty when in flower, but the pears' flower doesn't smell good, and the trees in general are prone to disease and to winter breakage, so are particularily short-lived. I am sure there are others, but this gives you some to go on with.

SW Alabaster is lovely light iff white but it is in the Yellow Hue family and that core characteristic in North facing space could show more predominately. I would need to see your furnishings and rugs plus better pictures of the flooring to make a better informed choice for you. Lots of great off white choices but good to understand what you plan for the room.

They certainly add weight to the room. Painting them won't change that. Part of the beauty of stone is the variation-painting makes all surfaces equal and flat and less flattering IMHO. I too would have suggested you go with the color not against it as you did with your furnishings. Saying that my parents had a circa 1950's HEAVY black bedroom suit of furniture. Over the years my mom tried different décor options to flow with the black. Gold is her current trend and it does look good. Very formal not as contemporary as the lines of your current furniture. The black is fine--it's the grays I would work on letting go.

A Farrow & Ball colorist suggested FB Bone for my N facing LR with FB Skimming Stone ceiling. I had them both color matched to Benjamin Moore paints. Look at BM October Mist. It is their color for 2022