Unless the mailman drops something into the middle of a rose bush, thorns are really a non-issue! And even dwarf camellias will exceed the size of the previously considered Knockouts so not sure you can make comparisons. Camellias - if you want them - need to be centered in the bed, not placed along the edges. Pick something much lower growing for that position.

Agree. The word, "dwarf" is so often misleading. It means smaller than the full size, but usually, that's still quite large. In this bed, it the 4' band near the edge, you need things that are more like groundcover/perennial in size.

Got it. People keep suggesting junipers, which I really hate as I had to deal with pulling so many out of a previous garden. I will keep searching.

I don't necessarily agree you have to have something short by the mailbox. With your mountain setting, house siting and circular drive so close to the road, some privacy for the front entry of the house may be desirable. You don't have to plant your evergreen flowering shrub butt up against the mailbox. There is plenty of room for dwarf camellias in the front bed, even if mature dwarf is 8 feet. Camellias handle light shearing quite well. Plant your groundcover around the mailbox.

Go camellia shopping. This site would not fully load for me. I think a thunderhead cloud is about, and satellite internet, ya know.

https://www.kinseyfamilyfarm.com/nursery-plants/camellias/