Also relevant: cards themselves could have a type: are they posing a question? are they a summary of something else?
Being of a particular type and having a link that places it in a relationship of a particular type are often two sides of the same coin.
Using lowercase for properties and uppercase for classes: if you are someone's father you are a Father. If something has you as a colour you are a Colour.
I need to look up how Dick Hudson's Word Grammar work deals with this "redundancy" as I seem to recall he does.