Yes but do it now - it will very quickly be too late if you don’t.
I made the mistake of planting two autos I thought were both bad genetics and thus would die off in one planter - now I’ve got two nearly full-sized plants competing for root space. I have another of the same strain in her own planter and she’s faring much better in terms of size and flower production than her sister seed in the shared pot.
Here’s the 2 plants sharing one planter:
And the one plant in her own:
She’s the front and center(ish) plant in the group photo:
20/4 or even 18/6 is good for autos. I like 18/6, saves me 2 hours of electricity every day. But one thing to learn early is what DLI is and does for your plants. It’s essentially the maximum amount of light a plant can utilize in a day - if you can hit ideal DLI without running your lights 24/0, then there’s zero reason to do it.
You can read about DLI here, Nicky is much more knowledgeable than I am. Start using DLI
Yes. But it’s a pain. See the shared planter above - the issue is the root zone, not really the ability to spread them up above ground to share light better.
Move the youngest one. Her roots will be less established and should be easier to transplant into her own pot.
Regarding transplants - I’d only do it once if you have to transplant at all. So if they aren’t already in final homes, get em there on the next transplant.
welcome aboard.