Concord CA has some warmer areas, so you might really be in zone 10, but most of it is more like zone 9. I am near you, and based on plant performance I seem to be zone 9b. If you are out of the wind, but near the top of some hills the cold air might drain away well enough that you do not get as cold as zone 9.
Shasta daisies are pretty tough, but we are having an incredibly hot spring. Almost setting records for heat.
If I had just planted Shasta Daisies I would put up some shade to protect them in the heat of the day, and water almost every day if they came from 1 gallon cans or smaller. Maybe 1 gallons could go every other day, but with temps in the 80s most days, and almost 90, new plants need all the help they can get. It could be that something is eating the leaf in the second picture, or it might be a leaf that got damaged in shipping, or when you were planting it. Looks almost torn, rather than bitten.
Roses in our area get several diseases. The best way to deal with it is to spray regularly. When I worked at a nursery the roses got sprayed every week with a rather mild product that killed insects and reduced the fungi.
The only way to deal with the fungi is to spray BEFORE it gets on the leaf. You are creating a barrier that the fungus spores cannot grow through, so they cannot invade the leaf.
The main fungi around here are black spot, rust and powdery mildew. Iceberg seems to get black spot more than the other diseases, so if you do some research, aim any sprays or cultural practices at controlling black spot.
The main insect pests are aphids, but a few others might be a problem on certain varieties. Thrips, weevils and whitefly can attack roses, but it seems some varieties are at least somewhat resistant.
