I used to have a small shady sunken garden so I can understand your position. I grew hedera colchica 'sulphurheart' up the wall. Its one of the ones with big glossy leaves - in this instance green with yellow variagation. It'd need some support at first, but will self-cling once it gets the gist. Tough as old boots but more interesting than common ivy. Also fiarly quick to get going, which many ivies aren't. Once its covering what you what an annual hack of anything spare and pulling out the odd brown leaf is all the maintenance it needs. You can underplant with evergreen plants such as heuchera, plus certain ferns are evergreen, euonymous fortunei is a small shrub that isn't fussy and comes in a gold and green variety, and perhaps the golden variagated sedge (carex) which also keeps its foliage all year. You can put a nice white daff such as 'thalia' under these plants and they'll just grow up through them every spring. Hardy geraniums will also grow in tough conditions, and whilst they're not evergreen, they do flower for a good long time - especially if you cut them back when the first lot of flowers is over - and it is nice to have a little bit of change through the seasons. Bedding will be tricky in so little sun - the non-dangly type of begonias should cope, as would violas/pansies, but that's probably about it. You could always squidge some into any gaps though. I used to have a couple of wicker 'witches hat' hanging baskets on my wall poking through the ivy. I put white muscari and miniature daff bulbs in the bottom, and then filled above with winter pansies. When the pansies were past it and the bulb foliage yellowing in late spring, I emptied the lot, dried out the bulbs to keep for the next year, and replanted summer pansies and golden lysimachia in. Not a lot of faff or expense but did brighten the place up!
Ivy is toxic if eaten, but my 3 and 4 year old boys never have. They knew from before they could talk the difference between people berries and bird berries. The colchica ivies tend to flower and fruit only when mature, mainly up high and usually in sun, so I wouldn't worry. They don't look appetising, either.