I think you are right about the Piazza (It seems that the information is inconsistent on the internet about this) I don't think it falls into this category.

as for the rest some of them are already listed as Origin Germany.

http://www.muenster.de/~mnickel/framee.htm

I think they are more than just a "little based" on each other but it is fine to leave them the way that they are already listed.