I wouldn't do anything now. If they turn into areas of dead bark by pruning time, it is a canker fungus. Cankers are, or become, pretty large (1" or more) with concentric color zoning. Normally we prune to a budeye at least 1" below these. If smaller, it could be a lesion of blackspot or something similar. These often develop on green canes in the fall. Apparently they are not directly harmful, but release spores in spring. This may be of no concern on KO, as the leaves are resistant. Also green canes may go spotty for a while as they change color in the maturing process. I normally notice this in spring/summer, though. Usually, I completely ignore my roses from shutdown in late November until pruning time in late March. It spares some anxiety and fuss. I don't know that any harm has resulted from this policy.

A grouping does look good. I'd plant them into the garden now so the roots can get established. Even the hardiest roses can die the first winter if the roots have not had an opportunity to grow into the surrounding soil. August is a really hot dry time to transplant a potted rose. Unless you water regularly and deep you could lose them especially if the soil falls from the roots when you transplant. Nature size and planting distance is determined by your growing zone. Pruning can be easy. After each flush of bloom, allow the flowers to fade some. Use a pair of hedge clippers and remove the dead blooms along with a inch or so of cane to shape the bush. In a few weeks new buds will form along with new growth. You'll have more flowers within a month. Yearly pruning should be done in spring. Remove winter killed canes and dieback along with any damaged ones. Cut back as far as you want to shape the bush and keep it in bounds. As much as many rosarians complain about Knock Out being the only roses available in many garden centers, their ease of growing and hardiness encourages many to grow roses again. The desire to grow roses soon entices them to try other varieties.

Goodness, my roses have red spots and silvery patches all over the place, especially fall through spring. Young canes turn various colors as they mature from green to brown or gray. These can start as red or purple spots and streaks, yellow flushes, etc. Purplish red spots and silvery patches can be from various nearly harmless fungi. Red spots can also be black spot infections of the bark that will carry the disease over winter, or the beginning of canker infections that will kill a patch of bark. It could be a reaction to sunlight. Don't be alarmed, however. You will probably never know exactly what these spots are, and chances are you will not notice any resulting problems. I just regard cane spotting as a normal thing in my climate and ignore it. If cankers appear in spring I will deal with them then.

Shots of the flower in all stages from bud to spent, leaves, canes and whole plant shots are always helpful. Yes, for the most part all roses require the same care. 6, preferably 8 hours of sunlight, about an inch of water per week, some fertilizer monthly and some pruning as needed to take out dead wood and keep the shape is pretty basic to all roses. In your zone you don't need to worry about things like winterizing. There are some exceptions in the pruning category but those are for very specific types of roses and yours does not appear to be any of those types. Keep it watered but do not let it get soggy or stay very wet for a long time because roses don't like soggy roots. Feed it any type of well balanced fertilizer. What ever you use on the rest of your garden will work just fine as long as you feed them regularly. In your zone I think most people do a hard "spring" pruning in February but I'm not in your zone so you may want to check that with a local nursery or better yet, contact a local rose society. They will be able to give you very good accurate information for your area. You can locate a local society by going to the American Rose Societies web site. They have a list of them on there. Really, roses aren't any harder to care for or require any thing more than what any perennial plant needs. So if you grow perennials you can grow roses! Here is a link that might be useful: American Rose Society