I don't know if the idea was that the adult figure would be more interesting if dating (Mickey & Minnie) rather than tied down in a marriage, or it was prudery (so that the younger characters' very existence would not imply that the older characters had engaged in any sexual activity).
Aunt Fritzi is NOT a lesbo.
She may have experimented a couple of times in college. But she is not gay.
Last I read, Minnie was addicted to the crack cocaine and turning tricks down on the seedy side of Sunset Blvd.
Aunt Fritzi was HOT.