^Metamorpho was created by Bob Haney and Ramona Fradon in 1965, only four years after the first shapeshifting version of Clayface, Matt Hagen, debuted. (The original 1940s Clayface, Basil Karlo, was just a horror actor in a mask.) So the two characters are from the same generation of comics. Metamorpho's powers are broader than Clayface's, since he can transform the elemental composition of his body rather than just alter its shape.
You're right of course but I think that a genealogical-generation is a 5th to a 15th times the duration of time as a Fanboy-generation, and that neither is static or constant in relation to time.
Jason Burr, the scientist Bloke trying to letch Katana, is (one of the many peopel who has been) Kobra or will be Kobra... Who was a major antagonist to the Outsiders.
My hypothesis at the moment is that season 2 of Beware the Batman is going to be called (Beware) Batman and the Outsiders.