Sorry to hear about the loss of the babies. Young plants can be a lot more sensitive to sprays (even "natural" ones). They call it a "plant wash" so I'm not sure if that means you're supposed to rinse it off after, but 38% soybean oil is a lot of coating on the leaves so they might have smothered.
In terms of the droop of that one in the pic, that could be from lack of water or too much water, so tip the pot and see if it seems light. Black pots in the sun are really hard on the roots, so if you can wrap in lighter fabric or drop them into an old pillowcase, that will keep them much happier.
Are you sure you got clones from an autoflower?
Topping a plant can leave it vulnerable to splitting if you don't leave a long enough stem above the node you leave (the "
double H stump"), but a zip tie around the top node can make sure it doesn't split as well. You should keep an eye on it and make sure it doesn't cut into the trunk as it grows. When it gets tight, cut it off and replace it. Of course, if you have high winds you should have the plants staked up as well.
Here is how I do my topping: