I don't want to be rude to you but you're trying to get validation for your opinion from social media to win an argument, which is rather immature. This is disrespectful to your designer.
>In my opinion having the character in the logo is crucial to the marketing. How do I persuade her that we must do this?
These statements seem to conflict with each other.
Taste is highly subjective, but your designer is a specialist in visual communication and literally sees the world in a different way from how you do.