Do you mean are they too much together as sisters, as first name and middle name, or are you considering one of the two?
Because my answers would be no, maybe, no (to the question "are they too much")
Personally I like Seraphina and am not keen on Magdelena, partly because I have to fight reading it as Maudlin-a because of the college, but that's a very specific baggage I am bringing to the name!