Not sure why you're second-guessing the professional you've hired? If you're not happy with their design, tell them what concerns you have and ask them to come back with an alternate option. We haven't been privy to your original input session with your landscape designer, so have no idea whether his/her suggestions are meeting your needs. Working with a designer of any sort should be a collaborative effort between the two of you. Why spend money on hiring someone if you're going to crowdsource the design?

You have a spruce tree that is too close to the house. Its limbs are over the roof and may be touching the roof. It will serve as a squirrel ladder to your roof. Squirrels will explore every nook and cranny they can find, looking for a way to enter the structure. Red squirrels have been known to chew a hole next to chimneys to gain entrance. You must keep squirrels off the roof. Secondly, spruce needles are acidic and will be a nuisance to the roof and rain trough. Those tend to stick to the trough instead of flushing away during rains. You will be forever cleaning the rain trough, and the acidic nature of the needles will promote corrosion. During winter snows, the limbs can droop from 1 to 4 feet from snow loads. It will rest on the roof - very bad. During warmer weather, it will tend to keep the roof damp and promote moss and lichen growth - bad. This tree will only get bigger and its problem grows with its size. I'm sorry to say, but you need to cut this tree. It should have been much farther away from the house. Spruces do not have tap roots. As it gets taller, it may blow over in a windstorm. If you sanitation sewer line exits from that corner of the house, the spruce roots are avid water seekers and may invade you drain line. It is nice to have an evergreen out front to have a bit of greenery during the winter months. However, do not locate a large evergreen at the southwest quadrant from the house. It will shade the house from winter afternoon sun, the opposite of what is desired.

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.

Find a window that is near the size of those in the dormers. It also needs to match the number of panes (6) in the dormer windows. You don't need to mirror the dormers only the windows in them. You need a carpenter to cut a hole in the garage gable for the window, then place framing for the window on the interior of the cutout. The window is put in place, secured and trim to match the rest of the house is cut and fitted to the outside. Adding a vent uses the same cut and frame, but doesn't require matching other features unless you have other gable vents that you wish to match. Vents are made in square, rectangular, triangular, round, half round, arched and octagonal shapes. They should have metal screen or hardware cloth on the inside to keep small birds and such from getting into attic space. This can be added if not part of the vent as sold.