You mention not being green-fingered, but you've identified two essential considerations for garden planning - the amount of sun, and soil requirements, so that's a good start.
You plan on stones and encouraging nature.
So I would build on these ideas to create several shady rockery areas with larger pebbles and rocks, interspersed with a few dwarf or small deciduous trees, some shade tolerant evergreen shrubs, and spring bulbs.
The rockery stones will provide some focus and interest to the garden as well as shelter for a wide variety of insects and bugs, and will add a sense of cohesion with the ground cover stones.
The advantage of using deciduous trees is they will not be troubled by the shady conditions in winter. Similarly with spring and autumn bulbs - they can garner their energy from their leaves in sunny weather in summer.
A couple of ideas for trees that might be suitable -
Silver birch Trinity College is a small growing, graceful, upright silver birch tree. It's white, exfoliating bark develops from an early age, giving it year round interest. It has shallow roots so might be suitable for the site. Fine feathery leaves in summer and striking white bark in winter.
Dwarf Crab apple varieties - especially those that develop smaller berry-like apples, as they are likely to hold them all winter and provide valuable food in times of scarcity for birds.
Witch hazel - slow growing large shrub/tree with winter interest and scent, and a food source for many species of moths and butterflies
Amelanchier - the June berry tree - it comes in a variety of sizes so a smaller variety - perhaps Amelanchier Canadensis. It can be pruned into more of a tree shape rather than shrub if the space is limited.
Shrubs such as Amelanchier, Skimmia, Daphne, Aucuba Crotonifolia (Spotted Laurel) with berries, Sarcococca (Christmas box), Viburnum in a smaller variety, Spirea, Cornus (dogwood).
In an area of shade, you could also consider a small patch of moss lawn.