winter flowers

hellebores?

Try Winter flowering Heather (Erica carnea various named varieties) and Erica darleyensis, which tend to be a little taller.

Not sure about hellebores - they tend to have long roots and wallpots may not be deep enough. Another possibility is small ivies with variegated leaves - no flowers but evergreen leaves trailing from the pots

Yes variagated ivies and pansies look good together, put miniature spring bulbs in, tete-a-tete is a good mini daffodil also muscari (grape hyacinths) give lovely colour in spring, will cheer you up after winter!