1st picture looks like some sunburn...maybe from droplets (probably water)...but there does look like a piercing/chewing insect got a hold of one spot. 2nd picture is just some random anthocyanin pigment coloration...nothing to worry about given how much light it seems you're giving your plants. It's similar to the coloration that sometimes happens at stem joints.

The crucial point in your other post was that this plant was supposedly "several months old" (so it is really approx. 1 1/2 to 2 months old, correct?) and only "18 inches tall". That is the real problem I fear. A Celebrity, even tho it is a semi-determinate variety, that is even 2 months old should be much bigger plant - at least 3 feet tall. This is especially true with all the feeding you have given it. Now I see the problem. (1) Compacted soil - it sounds like you didn't use a soil-less potting mix but maybe used Miracle Grow Garden Soil for Vegetables. Correct? It is not intended for use in containers. And (2) no holes for drainage in the container so the water "collects in the bottom", correct? Size of the container - if it is a 5-7 gallon should be fairly ok but the combination of poorly draining soil and water collecting in the bottom of the pot which causes root rot may explain the small size. And the very stressed plant with the high temps explains the blossom drop. My suggestion would be to find a bigger container that has room for you to add some good quality soil-less mix to and still have room for this plant and then transplant this plant into it. Make sure it has drain holes in it. I'd pinch off all or most of the current blooms - they aren't going to amount to anything anyway so no loss - and keep it in the shade for 3-4 days. I think you should see a marked improvement in the plant within that time. Keep the plant alive and healthy until the air temps cool and you'll get some fruit set. I hope this helps get you some tomatoes. Dave

It`d be pretty easy to overdo the misting in a fence post as most of it will hit the wall and flow down.to the bottom of the pipe, When the roots get large they tend to restrict the drainage and they end up sitting in water. that isnt moving very fast. I guess you have a nozzle between each plant site? I would turn off the mist and time how long it takes for them to show signs of wilting. Turn the mist back on until they stand back up. then set the mist duration to 1 second and set the pause duration to half of the time it took for them to wilt. If they start to wilt cut the pause time in half again after you`ve got them standing back up. After a few iterations you`ll find the ideal settting. Its best to fix the mist duration and just vary the pause so they get many short mistings rather than fewer longer mistings. ie; aim for little and often

i would carefully trim off and discard all that lower growth before treating. take pictures after a few days to monitor the spread.. also note where it's starting/beginning. is it randomly on parts of the leaves, or does it start at the tips or edges then progresses inwards.. fungal diseases are usually very spotty, meaning they start on random parts of the leaves and not typically from one direction. the upper growth (top of image) that is starting to show symptoms appears to be starting at the tips, then uniformly progressing towards the base of the leaves, which could mean that it is not a disease, but a nutrient deficiency. as mentioned, i definitely would start with a fungicide treatment first.