I can't tell what the existing brick is doing--do you want to install rocks there? I can't help with that. But on the boxwoods--I thinks it would look nice to continue them under the window to the right. Remember that there are several different species and cultivars of boxwoods. Take a piece from yours with you to see if you can find matching ones. Do you know what the deciduous shrubs under the windows are? Just in case they are worth keeping? If you can continue the boxwoods and put your burning bushes in front of them, then I would want a low evergreen border. I agree on taking out the junipers. Where are you? location and zone will help with suggestions.

I don't want to take all the fun of selecting shrubs away from you! Check locally and see what plants are easy to maintain at the sizes shown and have the personalities (leaf size/color/flowers/evergreen, etc.) that appeal to you. There would be a few options. The flanking space is that to each side of house front. We can't see how the house fits into its surrounding.

The first thing you need to do is reconfigure that walkway. The landing at the base of the steps is skimpy and awkward, demanding an immediate left turn. And the walkway itself is far too narrow. Should be at least 4' wide....5' is even better. Once a proper walkway is defined and sited, you can/should increase the width of the planting beds, especially on the walkway side, to accomodate better plantings. Anything you do now afa the plantings are concerned will have to be redone or possibly replaced once the walkway is restructured so save your time, effort and $$ and address that before you do anything else. Moving, adding or replacing shrubs/trees now is just applying a bandaid to a poor design situation.

I've noticed that whatever size is printed on the tag or is claimed on the Internet, is about half of the real final size. In their desire to see quick results people are prone to getting fast growing plants that soon get out of bounds. I think it's better not to rush it as time seems to pass quickly as soon as one focusing on other things. With water and fertilizer I find most plants to grow reasonably fast. There are always exceptions but as a general rule, they do.