Many varieties renowned for hips grow large. You won't be able to keep them small, so select them with care. The roses in my garden are more or less grouped together, so they look great in flower but pretty drab afterwards. Good cultivation and growing conditions will encourage your roses to grow new shoots low down and to stay leafy near the base. Bare legs indicate pruning too lightly, so prune harder.
Numerous plants make good companions to roses.
You could plant thyme to spread under the plants or heathers to flower in the winter. Summer bedding can make a colourful edge. So long as you don't disturb the roots of the roses and you stay with plants that are not too vigorous or invasive, you can let your imagination loose. Companion plants will act as hosts for pests. But you will be wasting your time if you spray for greenfly and only do the roses, as the other plants in the bed need to be treated as well.