I was going to suggest the same as celery. absolutely remove the large shrubs. I'm sure any local nursery can suggest the correct plants for your flower bed. Some other ideas: Just painting your garage door a darker tone (all of that bright white against the dark red brick is too star) and adding some of the carriage hardware to it, makes such a diff I gave you a softer beige, but her dark gray would work too. here's a warm, dark gray w/the carriage hardware (you can buy this on Amazon for less than $40) Looks good w/the dark brick, yes? and don't forget to get some new garage lights that aren't white. any of these would be fine. see these lights? and the hardware on the door? dark red brick, with all of the warmer (don't do a blue gray!) trim and door. since you have some rock in the beds, you could do something like this w/the pots around the front door (which you could also paint. I gave you a peacock blue) just look at the flower beds not the house. they used mexican pebbles and large pots this would also work w/your house color

Do consider that you are going to be waiting a long time for a 6' tree planted even as close as the center of one of your lawns to provide any significant amount of screening or shading of the house. But which particular window are you thinking about? A tree lined up just right with one of them and planted close enough could provide an adequate level of screening pretty quickly - maybe even immediately if of the right size and shape. With it also casting a moving shadow over part of the house some day. Otherwise you could block the street with solid fencing and/or hedging/screening plantings consisting of or including dense shrubby kinds. Usually river birch is not affected by bronze birch borer, with up here anyway it being the European, Himalayan and paper birches that are being hit now that the pest has come this far west. For instance the next door neighbors to a friend that lived near Seattle had two cut leaf weeping European birches and one river birch in their back yard. When the borer came to their neighborhood the European birches were being drilling out and dropping branches on his side of the fence in no time. Luckily the neighbors were quick to have these cut down. Providing in addition a much better view of the river birch, which as of the last time I was on the friend's property was still standing there looking intact.

Thanks, Sigrid. What I mainly want is to make the house proportions look better - wider and not so tall. I'd also like to change the style to something more tropical, less manicured. Those rounded shrubs are holly trees; they're not covering any windows but I would still like to replace them with something less heavy looking, such as roebelenii palms. More pics to come when the angle of the sun changes!

Rock/gravel mulch jagged edged not smooth would work on that slope so long as its not walked on much. A nice retaining wall could look great but would cost more. We had a low slump block one put in the front of our house and it really improved the look of our yard as well as holding soil back.