Hiya Alex,
A very interesting question and one really for someone who has experience with growing under your exacting conditions (which would not include me). I would however make a few comments. Firstly, do you have an alternative to a north facing window? it would not be a problem during the winter but in the summer most orchids like bright diffuse sunshine even if described as semi-shade loving. Though you may get satisfactory results if the plants are kept close to the glass to maximise the light. Secondly, your diurnal temperature range seems very narrow especially if you are living in a house. If you live in a well insulated apartment it would be more understandable. So if you haven’t already done so do confirm the range with a max min thermometer. Most orchids prefer a day/night shift of at least 8 degrees although perhaps true equatorial tropical orchids might prefer it more constant. If your temperatures are accurate you could certainly be good for “warm” growers but it would be perhaps then be ideal if there was rise to the mid-twenties during the summer days.
Glancing down your list of genera, if it were me, I would avoid Sophronitis as they are notoriously fussy cool growers demanding high humidity and bark-mounting. Cattleya/Laelias generally require copious light to make sufficient vegetative growth to push out their flower-sheaths but many people do have success growing them indoors in Ireland on a bright windowsill (check out: https://www.youtube.com/watch?v=-ij86VX9t3Q). I think Encyclias, Brassias and many non-reed stem Epidendrums might do very well for you as they like warmth and are small growing. Maxillarias are quite adaptable particularly species tenufolia (coconut-scented). Stanhopeas are big basket growers so very messy for the home (believe me, I know!) and the flowers (though utterly magnificent)only last a few days each year. Phrags might do well under your conditions and are popular indoors but do require lots of high quality water and can grow big. Of course there are two obvious low-light, warmth loving small plants that would excel for you….Phalaenopsis and Paphiopedilum!
So in conclusion, I would most importantly confirm the accuracy of the temperature range you quote, it seems odd and definitely ask your question at a society meeting as other members may have more imaginative suggestions and opinions!