See link on pear scab (aka blackspot). As I mentioned earlier, immunox should take care of it, although as the article says, it's not as severe or devastating as apple scab. Regarding your apples, I posit leafhopper b/c the upper leaves of your apples are curled, a result of the leafhoppers sucking the sap out of them. If you can kill the leafhopper nymphs (often seen on underside of leaves) it will be easier to control damage in future. Insecticidal soap, pyrethrins, and imidacloprid are all apparently effective, esp. the last as it's systemic in leaves -ie suck the sap, and bang your dead:).Honestly, you could probably ignore all of it and be OK, as they're not devastating issues. Here is a link that might be useful: blackspot

On the leaves, looks like Whitefly larvae. On the soil looks like harmless slime mold, a fungus that will grow on rotting mulch or very high organic soil under the right conditions. I am not sure as the Pics. are small and my computer is old. Look these two up on the net and see if either match.

Yeah I think you're right about the white; looked again today and it was gone. The scale on the last plant if there is subtle, but how about the numerous non-subtle brown spots, some of which look eaten into the leaf? Some kind of mite? If so, here's the combo I've come up with: Acephate - Amazon: "97UP 1lb bag Generic Orthene Insect & Fire Ant Killer" - http://www.ext.colostate.edu/pubs/insect/05507.html says "Insecticide with some effectiveness against spider mites. Systemic." Forbid 4F - eBay: "Free Forbid 4F Miticide Spiromesifen 1/4 OZ free gift when u purchase 3 pipettes" - "Like Avid, it is translaminar. The active ingredient, spiromesifin, while not systemic (i.e., it does not move through the plant’s vascular system like, for example, Merit does), is absorbed by the plant’s leaves and will move from the tops of the leaves to the bottoms where the mites feed." A lot of the more mainstream systemic products use Imidacloprid, and while they don't claim to work against mites, they also don't mention that one reason that spider mites become a problem is insecticides [such as Imidacloprid] that kill their natural predators.

If there are translucent flecks in the leaves, then I think it is most likely insect damage. Spider mites, maybe? The only things that bother my thyme are leafhoppers. They cause those sap-sucked flecks, but they fly all over the place when I touch the plant so I feel as though you would have noticed them if they were present. Variegated leaves can burn easily in the sun, but it will not cause the flecking. If you're sure that it's spread to your other herbs, then I don't think it's a disease. The only diseases likely to affect all four of the plants you mentioned are those caused by Rhizoctonia solani and the water moulds. You would be seeing the symptoms develop rapidly stem-by-stem, and they'd involve heavy leaf loss or wilting. If you've got healthy leaves and damaged leaves on the same stem then it is unlikely to be one of those diseases.