A. You are right that the simple literal reading of the texts seems as if Aharon went along with it and was a willing participant in the idolatrous affair soon after the Giving of the Torah at Sinai.
Midrashic sources and biblical commentary explain that Aharon’s involvement was a stall tactic, hoping to delay it each step along the way. For example, when he said, OK, get your wives to give up their gold jewelry – he figured they would be reluctant to give it up (and indeed the Midrash says the women would have nothing to do with it). Or when he said after the calf emerged from the fire: let’s make a celebration for G-d tomorrow! Aharon wanted to delay, because he knew Moses would be coming down the Mountain any time now.
I am not sure why the verse chooses to depict it as if he was a willing participant. But often the verse “requires interpretation” and we can’t get the full picture going only by the written word.