Penelope is fairly popular now in the US, but Jemima isn't and is highly unlikely to become more than a Hollywood hipster statement. In the US, there is a very famous (and quite good) brand of pancake mix called Aunt Jemima, and while the logo of Aunt Jemima is updated and benign, the term Aunt Jemima as applied to a black woman is quite offensive, kind of on a par with Mammy.
Jemima and Penelope both seem goofy and cartoonish to me, and together they are even more so.
I think, therefore I judge.