I'm so happy this thread exists

I was sold an "Ameraucana" but I'm sure it's an EE, as it came from a large hatchery and I know that's usually how they try to sell the EEs. I don't mind, I'm happy with the choice!
We ordered 4 chicks (2 RIRs, 1 Plymouth Rock, 1 EE); they are just over 4 weeks old at this point. Their feathers are coming in, and I can pretty easily identify that two are pullets based on their body types. Another I'm fairly certain is a girl, but
our EE (Tina Turner) has either really determined that she is the top of the pecking order or has truly started to show roo qualities. I'm going to refer to "her" as a "her" for the sake of explanation.
She's the hardest one to catch and HATES being picked up, and constantly tries to escape my grasp when around the other chicks.
She's totally fine if I carry her out of their sight, and then she acts very friendly, mellow, calm and stops trying to escape my grasp. But, she goes ballistic when she gets within eyesight of the other chicks. When I set her down, she runs all over the place and gets in everyone's face, like she wants to make sure they're all ok. (I know not all chickens like beying held, but we've handled ours a lot in the last four weeks to get them accustomed to us and being picked up. Her objection to being held is a recent development.)
None of the other chicks seem to mind her behavior, but I think she plays favorites to one of the RIRs and is always trying to get next to her and get in her business...
I can't tell if that's a display of dominance from one pullet to another as they vie for a place in the pecking order or if Tina has selected her "favored hen" (can they even do that at four weeks old?).
Her comb started coming in first, and is barely tinted red. She is larger than the others by quite a bit, but that could be a breed difference as we have three different types across the four birds. Her behavior has definitely escalated in the past week or so, and even though it is in no way violent towards me or the other chickens, I'm observing her a lot more.
Is it possible to sext based on this behavior? Essentially I'm wondering if this is dominant cockerel behavior or a pullet vying (and ultimately claiming) her roll as the queen bee. We are first-time chicken owners and despite my months of research and obsession with chickens, there is nothing like owning chickens to really get a sense of what they're like! I'm pretty certain Tina is a cockerel, but it's just a hunch...
I'll post an update with photos soon. I don't have any recent ones with their closer-to-full-grown feathers right now. Any help based on behaviors, though, is appreciated