I don't garden in Arkansas but in southern Missouri so it is very similar to yours. Unfortunately I don't do much fall gardening so can't help with the individual questions.

Are you familiar with Arkansas University Extension service?

They should be very helpful. They will also have a link to the Master Gardeners you can call who should be helpful.

Here is a link that might be useful: Arkansas University Extension

I do more flower gardening than veggie gardening so I can't answer your questions. Someone else may be able to, so be sure to check back in.
I wanted to welcome you though! I'm glad you found the Ozarks Forum. Gardenweb has a Vegetable Gardening Forum too. You weren't wrong to ask your question here. I just thought you might want to check there also if you don't find what you need. Good luck with your new garden.

Here is a link that might be useful: Vegetable Gardening - Gardenweb

Welcome to the Ozarks Forum
I'm actually from NE Kansas but the people on this forum are so friendly and helpful that I feel very at home here :)

I havent grown your specific crops either but with Chard I cut the outer leaves and leave the smaller ones to grown. They keep producing and producing. Very tasty sauteed with leeks and a bit of garlic...yummm

I'm glad you're having success with your first garden. This was a difficult year for alot of people.

I don't know the answer to your question but that never stops me. When I grew kale it didn't grow at this time of the year. What growth I got was earlier and mine didn't make it through the winter very well. Collards on the other hand lived through the winter and started growing again in spring. I am not a vegetable gardener so I am no expert. Besides the vegetable gardening forum, there is the Oklahoma forum with many vegetable growers and a similar climate.

I'm over here in eastern Ok in z6b and have had some success with the plants you mentioned.

My kale was planted in Aug and is plenty big enough to pick now. You may be further enough north that the cold weather has slowed yours down. However Kale is very tough and cold hardy. Last year I piled oak leaves around mine and it overwintered and resumed growing in March when we resumed eating it. As mentioned kale, like lettuce and spinach is usually harvested by picking the largest, outermost leaves and letting the smaller ones grow.

Chinese cabbage grows out in a rosette first before it produces a head. If yours hasn't started heading by now, I would protect it. Last year DH built a simple cold frame--just a 4by4 wooden box with screenwire over the top to keep out the grasshoppers--and that gave enough protection to my chinese cabbage with a heavy blanket spread over it that I picked ch cabbage well into the winter. In fact one plant overwintered and never made a head but went to seed and right now I have a couple small ones ready to pick from those selfsown seeds.

Spinach too is very cold hardy. I have had it survive 0 F and come back the next spring and have picked it and then let it go to seed. I also piled leaves around the spinach. Only the hardiest of lettuce survives the winter here, but sometimes in a mild winter it does.

Good luck. You've come to the right place to learn about vegetable gardening.