On Lucinda's team Claire suggested the split, and on Helene's team it was Michael. In both cases the project leader merely accepted the best idea the team produced. Lucinda got the better plan because Claire's idea was better than Michael's. It wasn't because Lucinda was better than Helene.
On the dress selection the point is more valid. But even there, I think it's clear that Raef made a better argument than Michael. Raef even convinced Claire, who had been championing the high-street dresses. Helene's team was hamstrung by the earlier decision. That the choice of dress lost them the underwear was more bad luck.
If the team leaders had been switched and Helene had been leading Claire, Raef and Lee, I think she'd have won. Not because of her, but because the team was so strong. It was the two finalists and Raef! All Lucinda had to do was not get in their way.
I will grant that Lucinda switched her team around when it wasn't going well, and Helene didn't, but that had no effect on the result. (And we don't know if Lucinda was following a suggestion from her team then, as well.)