Answer: From a design sense, it sounds like you have a lot of variety going on there and I suspect the plants may crowd as they mature. Depending on the style of your house and your personal preference you might consider limiting to fewer different types of plants for a less cluttered, more serene or elegant look. And depending how they are to be arranged, you may not have room for one of each.
Japanese hollies and the blue hollies are often used as foundation plants because they tolerate clipping to size fairly well, so say, a three foot height/width would be reasonable. Left untrimmed, the Blue Girl holly will eventually grow to about eight feet high and six feet wide in a nice fairly symmetrical natural pyramindal shape. If you repeatedly clip a female holly to maintain it at a certain smaller size, you will not have any berries on it. Also, to have berries you need a suitable male holly (such as Blue Boy) nearby. I mention this in case the berries are important to you.
Based on my experience, I am a little concerned about crowding. The Gold Lace junipers will spread outward to about six feet across. The Japanese hollies can be kept reasonably small, say three by three feet, with pruning.
The spirea's mature size depends on which type you have. A "Goldmound" or "Limemound" for instance grows to about three feet tall and four feet across, "Snowmound" can easily grow to five feet tall and wide, and Spiraea x vanhouttei 'Renaissance' can easily pass five or six feet high and wide. These shrubs can not be kept smaller by pruning.
Depending which cedar you have, it might be a large evergreen tree (Cedrus atlantica 'Glauca' or blue atlas cedar grows to 60 feet.) Or, if you have the weeping form that is trained to a stake, keep in mind it continues to grow wider and will look best in a lawn setting where it is not crowded and has a plain backdrop where its exquisite form can be appreciated.
Unfortunately, it is difficult to consult on specific design and placement issues long distance. You might want to make an approximate scale drawing and see how these would fit into your space when they mature. I know they look very small and sparse when first planted, but they do grow -- faster than many of us would expect. I hope this helps.
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