I never really understood how the Witch of Miracles Bernkastel and Frederika Bernkastel are different. Truth is the only When They Cry games I have played was EP5 and 6 of Umineko, so I haven't gotten any clues to Frederika's background.
First of all, they both have the same (last) name. Is Ryukishi07 just screwing with our minds then, or is there a connection? Frederika's only featured in Higurashi as an author of poems placed around the different games and mangas. And Bernkastel is simply just a character from Umineko.
Personally, I think there's no connection, and Ryukishi07 only really loves the character design of Rika (Hence we now have Bernkastel, Erika, and even Featherinne looks very similar, if you look closely)
And does even discussing the connections make a difference? If we put the pieces together, it won't help the Umineko truth, I guess xD.