You can transplant them outside before the last frost. After they are acclimated to outside temperatures, they will tolerate frost and freezing well. The planting date can be hard to determine. I think around April 1st is a good time to plant them outside. Before planting, I would monitor the weather for a week or so to see if the temperatures are fine. If temperatures are in the 50s for highs daily, and lows around 35-40, I would plant them. I would wait if the highs/lows are lower. If you plant them on April 1st, then you want to start the seeds anywhere from 4 to 6 weeks before transplanting, depending on the size of plants you want. That would be around now. Others in your zone may have a better time frame. Better yet, if you give your city and state or general area of the state, others can give an even better estimate since the USDA zones cover a large area with different climates.

I was going to ask the same question about my radishes and chard, which did the exact same thing. I'm wondering if theres some missing micronutrient in the soil. But I can say that with the chard, which were sort of laboring when they were all bent to the side, I piled up some soil/compost mix around them so that it supported them straight and they had that skinny crooked bit supported with soil, and the week after doing that they really just grew like crazy. Its not scientific research, but on my experience I'd try to add another half inch of soil to the top and help straighten them out.

I started a flat of cole crops first of july. I put them out in my Hoop house(which doesn't have the cover on in the summer)the first or second week of August. I did 2 kinds of sprouting broccoli, which are specifically bred to overwinter. You cut the head at the first sign of it, and they are supposed to sideshoot like mad real early in the spring and continue for some time. The seed pack had days to harvest as 220, reflecting the need to grow in summer, overwinter, then sprout through spring and into early summer. They are supposed to be extremely cold hardy, and if I remember they have some cross with kale in them. Kind of a commitment, but I'm going for winter/early spring harvests out of the hoophouse as much as possible. I also had January King cabbage in the same flat. The sprouting Broccoli plants are about 2 feet tall and wide, so they are big. The cabbage(again, a winter variety) is just starting to form heads now. They are also bigger plants than I was expecting. We have a few more days in the 80's, next week should be in the 60's for a high, and I doubt we will climb into the 70's much after the cold front comes through, so I will be covering soon. I was also thinking of putting in some fall clearance plants from the nursery, but I don't know that they will have enough time to mature into anything. My understanding is for the plants to be approaching maturity when the cold comes, and they grow under protection(slowly) throughout the cold winter and you harvest them as needed. Come spring warm up and longer photo-period, they start bolting. I dunnno, might try anyway. Check out Territorial Seed's winter growing catalog, there is some cool stuff in it, pun intended.

Likely caterpillars of one kind or another. Don't know which specific ones are busy at your place, but the key is to look closely at top & underside of leaves. At my place, the current bad guys on the cabbage family crops are these: 1. imported white butterfly (cats are up to 1 inch long, velvety green color helps them bled into the leaf. 2. diamondback moth -- very small cats, about 1/4 inch, also small pupal cases webbed to the leaf. These cats make "windows" (eat cells on surface, only) also holes.