It may be Cryptotaenia japonica f. atropurpurea

Couple of thoughts.......avoid any overhead watering. When you need to water, do so at the root zone and do so thoroughly. Excessive water on foliage can lead to fungal diseases and leaf spotting. Second, you may have over-amended. Soil conditions radically different from those the plant was grown in can lead to shock. Ideally, if amending is required, it should be done over the largest possible area, never just the planting hole. And never a good idea to fertilize immediately on planting - the plant can't metabolize it. The good news is there is nothing wrong with your plants. The purple-brown coloration is just a reaction to cold, common to many plants, especially if not acclimated to the area or with more foliage than established inground plants may have. The spotting may be just a touch of leaf spot but nothing to get concerned about. Just change your watering methods and pray for warmer weather :-))

This image is from the adjacent plant, watermelon beefsteak. It's more affected by this than the cherry. It looks like the leaf I pulled off earlier is more of an exception than the rule, in that the veins on the leaves are fully affected. I'm hoping it isn't the disorder that is uncurable.....

That's a common issue that could just be nothing to worry about, or it could be a phosphorus deficiency and/or caused by cold temperatures. Looks like a fairly healthy plant to me... the yellowing lower leaf could be overwatering or time for dilute fertilizer. You could do a search for purple leaves on the hot peppers forum.