I'm trying to figure out why some of my plant...

I agree you should be happy, your girls look great so far. As far as the differences in how they grow, this is not uncommon with autos. Different seeds, even of the same strain, can vary from plant to plant. Sometimes you’ll only get one big main cola other times you’ll get a bushy plant with lots of branches. It’s just kind of hit and miss in that regard. But it should all smoke fine in the end. Good luck with your grow! 👍