Yup, as Rick suggests, sitting them on an old towel folded up to make a thick pad will "wick" the excess moisture out of the bottom of the bucket. Or if you have rags, or old T-shirts, anything cotton works best.
After that, I'd set them up on something that will hold the bottom of the bucket off the ground a little so that air can get under there to the drain holes. You'll also be able to check in future that when you water, the water going in is also (mostly) draining out. Stones, brick pieces, chunks of wood, anything will do.
I'd wait on any more nutrient additions until we see how the plants recover. Once you've let the buckets dry out a bit - maybe don't water for a day or two - sparingly water in some 1/2 strength soluble fert and let's see if the pale leaves green up and the plants generally perk up within a few days. If they don't, the root rot caused by soggy soil may have you "flogging a dead horse" and it might be better to start over.
Rick's explanations are much more scientific but here's my simplistic version of soil science 101 - organic material is absolutely necessary to any growing medium. This is because the cellulose fibers that make up all current and former plant matter swell up like tiny sponges when they get wet and - this is the key !! - they shrink when they dry out, leaving air spaces in the soil. This allows the plant's roots to grow without rotting.
Compost is the gold standard of soil amendments because it is mostly decomposed plant material - tiny shreds of cellulose fibers that can work their way down into almost any soil and then do their expanding/contracting work to help incorporate air, as well as hold nutrients and water at a rate useable to the plant.
So, having straight sand down in the bottom of your buckets might sound like a great idea on the face of it, but without the little sponges between the little pieces of rock, there's no air getting in there.
