Conifers have quite shallow but matted roots, so planting near them may take a bit of digging out of roots to create decent-sized planting holes. As the conifers are dead on your side, hopefully their roots won't grow back much. As for shrubs, and not knowing your soil type, drainage or what sun the border gets, you need what I call "good doers" to give you as much chance as possible to achieve what you want. My suggestions are: the green and white varieties of Euonymus (not the dwarf ones) as they can be trained to grow upwards if supported by something. Berberis darwinii has dark green leaves and, if it gets enough sun, has orange flowers in spring. Escallonia varieties, especially the one with reddish flowers (?Donards seedling) which flower in summer, and perhaps honeysuckle and clematis. All the shrubs I mentioned are evergreen that will hide the conifers, they have leaves that should contrast nicely with each other and the background, can be easily kept in check by pruning so they don't overgrow outwards which will then help them to grow upwards, should be reasonably inexpensive and the last two flower at different times of the year for all round interest. Both honeysuckles and clematis will flower at different times of the year depending on their variety. I would dig in well-rotted manure, compost (including mushroom) all over the area to improve your soil texture and water retention. Make your planting holes twice as big as the plant's pot is and add more of your compost to the bottom of the hole, then add a good sprinkle of bonemeal to both the hole and soil backfill. Don't over-tread on the soil as you plant. Give the plant a jolly good douse of water, then repeat every few days even if you have rain so it can really get established.