10 Gallon? What are the measurements on these containers? I've had confusion with sizes, and these look great to me, I'd like something similar. The rule of thumb for lots of people seems to be 5 gallons for one of those plants, and if you have anything less, they will produce slightly smaller or less plants. BUT, if you have two per container, I think it would be enough for a first time gardener to see what happens :)

i watered with a full flow garden hose every two days. we were in what I call a drought (not sure if we were scientifically)for almost two months around Easter time. i enjoy walking around watering everything with the hose. I did give it some osmocote. i made sure that it wasn't root bound too. It was very happy and growing very well then all of sudden the leaves turned brown. it started at the beginning of the week and by the end they were all totally brown. i did put a single stake in about a week before the browning started because the SE wind was causing it to lean. i tied it to the stake with a pair of nylon stockings, so that shouldn't have harmed it. maybe the osmoscote. i was once told not to fertilize anything that just came from the nurser since they keep everything well fertilized??

You said you're a first time gardener. If you're not growing in a community plot and you haven't just moved into a place where the previous resident had a veggie garden, I would not worry about soilborne disease. Those take some years to build up, and the soil in a new garden is \unlikely to have them. Re: writing the plants off, I'd give them some time before I started thinking about pulling them. Moving plants established in the ground is different from moving plants from a pot into the ground, and I haven't tried moving established in-ground plants. But this is what I'd do: In the AM, I would expect the plants to look better after the hours of cooler temps and darkness. If a plant looked like the one in the background of your bottom pic tomorrow AM, I'd prune off some of the oldest, biggest leaves to try to reduce the water demand from the foliage. One that looked like the plant in the foreground I'd probably leave alone. I'd make sure to shade the plants for the next few days. If your tarp is opaque, that's fine for the next day or so, but then I'd probably switch to a shadecloth or something like a sheet that filters light but doesn't block it entirely. I would not get alarmed if the plants drooped during the hot part of the day for the next few days (sometimes, totally healthy plants that are not shocked do that when things get very hot, anyway). I'd remove any foliage that collapses (not just sort of soft and droopy but totally limp). And I'd really only lose hope in a plant if it totally collapses, as long as the variety is indeterminate. Although kind of wimpy when it comes to disease, tomato plants are super resilient when it comes to physical trauma and will surprise you with their ability to get past it and thrive. If you don't need that space for other things, give them a good chance. It's true that diseases may take advantage of weakened plants, but it's way more likely to be foliage disease than root disease if you're gardening in "virgin dirt". So I would be proactive and start a fungicide spraying regimen. I wouldn't start feeding them until new growth starts up again. This is just what I'd do. I hope someone who has experience moving established in-ground plants chimes in and corrects anything that's wrong.

I don't think you can expect any fruit until the days get longer (much longer) and the temps are higher. Greenhouse-grown tomatoes are getting a lot of additional light and heat this time of the year. If yours are out in the open, I think your window is closed until spring. BUT, from my experience, tomatoes will never thrive and be productive again after they've been exposed to temps below 45F on a regular basis. But Zone 10 could be a different story.