IMO, you must remove all of the existing shrubbery and replace it with things more promising. The existing shrubbery is wounded, downtrodden and has little chance of recovering. Plus, it was not chosen for low maintenance or excitement. Just start over. You stand a much better chance of making something good out of new plants ... planted a little farther from the wall so they have room to grow. A retaining wall is only necessary if you need to fix the grade for functional purposes, which doesn't seem to be the case. Instead, compensate for the falling grade by using a larger shrub at the low end and lesser height shrubs as the grade rises. In the area around the porch and farther left, you could get away with a single type of plant. (Any hedge that is part of a foundation planting should be trimmed level, not parallel to the grade ... so as to make the house appear stable.) Some color are around the entrance could help cheer up the overall scene. You really need to learn the proper way to trim shrubs as it will make an astounding difference. In order to keep the lower foliage, shrubs must be trimmed wider at the bottom then they are at the top. Of course, select varieties that can stand the existing light conditions as well.

Check out this video by Rosalin Creasy, the queen of edible landscaping. She also has a Web site. Then follow any links from there. You'll find a lot of inspirational photos and resources online. Yaardvark's basic design can be followed, you just need to figure out edible plants with the shapes he has drawn that thrive in your zone. I'm not that up on edible weeping plants, but lots of big shrub-shaped edible fruits and there are also fruit trees that have a columnar shape (column shape) such as sentinel apple trees. Raspberries and blackberry tend to get droopy and weepy-ish shaped (fountain shaped). There are edible easy to maintain groundcovers too, like lingonberry, although they need acid soil to thrive so you may have to amend. I grew bearberry which also goes by the name kinnikinnick as a groundcover. It is not really "edible" so much as medicinal, where it goes by the name Uva ursi. Lots of herb ground covers like thyme and chamomile and some low growing mints. There's also wintergreen but that needs shade and can be fussy. Not too much in the way of edible evergreens although you can grow balsam or fraser fir in some zones and collect the needles for their scent and oil. With juniper you can harvest the berries and make gin. Some junipers are columnar. Some make good groundcover, a fairly common low maintenance option for small yards. Edited to add that you're going to have to be thoughtful about planting your front yard since most edible plants like sun or partial sun, and your sun is going to be filtered at best. Try not to plant things in the shade of other things, so watch where the shadows fall during a whole day at different times.

GG, how are you going to adapt the stream portion abutting the property line to that configuration, without turning it into a planted garden? (Which would be OK as in your pictures, but that would grow it considerably wider, extending into the lawn portion of the yard.) Still, the stream has a perfected edge, whether a hard material, edged grass or artfully placed larger rocks, which I have no objections to, and probably a preference for, but don't want to take the time to draw those!

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.