It's obvious you are a very loving & responsible doggie owner and that's wonderful! I have 2 dogs that play in the yard everyday and only recently learned that my aloe vera, Azaleas, Hostas & cyclamin, Chrysanthemums & Ivy are toxic to dogs, yet I've had them in the garden for quite some time. My next door neighbor has an avocado tree that hangs over into my yard and it has never been an issue. My biggest worry mushrooms! But as far as a screen~ I'll chime in with my suggestion~ Dodonaea viscosa cv. purpurea (Purple Dodonaea). You can almost plant it and forget about it. They are evergreen, very drought tolerant and fast growers and do well in our zone. They can get really tall & wide but not invasive at all. They need to be kept pruned (about once a year or every other year)for desired size & shape and to look their best when they get older, but are super easy to prune since the branches are spread out. A few cuts and your done. I think it would be nice for a cottage style as well because they are very informal looking. Just make sure you don't plant them in an area where you have other plants that require a lot of water because over watering will kill it. I have one in a long deep planter that's built in to my deck (approx. 3'deep x 8' long x 12" depth) and give it about 2-3 feet around the roots where I don't water as frequently as I do for plants at the other end of the planter. If you dont like the purple, there is also the green variety. Here is a link that might be useful:

What a shame to lose them. Nothing replaces camellias! My favorite shrub for shade. To me the companions that look well with camellias are azaelas & ferns. I read about oak root fungus after seeing your post and the bad news was the fungus lives on in the roots left behind from the infected plant. If that is what killed your shrubs, the others will probably die also. None of the plants I thought of were listed as being resistant to the fungus. And some would not look well with camellias IMO. But here are some I like for semi-shade. Brunfelsia Coprosma repens - love this shrub, leaves glossier than I've ever seen, handsome. Might look well with camellias. Fatsia japonica aka Aralia sieboldii - not so popular now, bold leaves. Might look well with camellias. Hosta - not really a foundation shrub but nice with ferns, azaelas & camellias in shade Hydrangea - shade type; not particularly pretty with camellias IMO Viburnum davidii - shorter shrub; V. foetens - hard to find, taller If the shade is a 'light' one, Murraya paniculata is a pretty shrub.

Question #2 is even trickier! Gary, I really don't know the general life span for coprosma. But if the decline happened that quickly, it does not point to an old age issue. I don't know which came first, but the plant has been heavily pruned. If some established plants get moderately-heavily pruned at the wrong time, the undergrowth can suffer from the sudden change in heat and sunlight. Then that damage might get removed, and the condition cascades from there. I believe coprosma is more sensitive to summer pruning in that regard. When I grew some ('Evening Glow') two years ago, I recall making a firm mental note to prune them in late winter, and not at all during the summer. But I don't recall where I picked up that information or if that applies to C. repens. Or if it was a factor that I am not a shy pruner. There is new growth coming from the lower stems. If the root system is healthy, you could choose to cut it back to about 10-12" and see if the fresh growth takes off, pinching as it grows to help the plant bush out. Riverside is still experiencing some hot temperatures, I believe, and will have some colder ones coming in the next few months. If you do prune back, you might want to wait until late winter, and/or temporarily provide some protection for the tender growth. Something like a piece of shadecloth draped over some small stakes would help.

First, take a good look at what is there so you can make a reasonably intelligent decision about what is needed. These simple soil tests may be of some help. 1.Testing for organic matter. Put about 1 cup soil (enough to fill the jar to 4 inches) in a clear 1-quart jar, with a tight fitting lid. Fill that jar with water and replace the lid, tightly. Shake the jar vigorously and then let it stand for 24 hours. Your soil will settle out according to soil particle size and weight. For example, a good loam will have about 1-3/4 inch (about 45%) of sand on the bottom. about 1 1) Soil test for organic material. From that soil sample put enough of the rest to make a 4 inch level inch (about 25%) of silt next, about 1 inch (25%) of clay above that, and about 1/4 inch (about 5%) of organic matter on the top. 2) Drainage. Dig a hole 1-foot square and 1 foot deep and fill that with water. After that water drains away refill the hole with more water and time how long it takes that to drain away. Anything less than 2 hours and your soil drains’ too quickly and needs more organic matter to slow that drainage down. Anything over 6 hours and the soil drains too slowly and needs lots of organic matter to speed it up. 3) Tilth. Take a handful of your slightly damp soil and squeeze it tightly. When the pressure is released the soil should hold together in that clump, but when poked with a finger that clump should fall apart. 4) Smell. What does your soil smell like? A pleasant, rich earthy odor? Putrid, offensive, repugnant odor? The more organic matter in your soil the more active the soil bacteria will be and the nicer your soil will smell, to a point. Too much organic matter can be bad as well. 5) Life. How many earthworms per shovel full were there? 5 or more indicates a pretty healthy soil. Fewer than 5, according to the Natural Resources Conservation Service, indicates a soil that is not healthy. More than likely that "native" soil just needs a lot of organic matter.