While looking through some Spassky games, a thought entered my head. What two openings are the most distant cousins in terms of character of play and stuff? I thought about things like the Closed Ruy Lopez and Budapest Gambit, but in both games, knights are often the main performers. I also wanted to see if there is a player who has successfully integrated these in his repertoire. Your thoughts?

The Bird opening's From Gambit (as white) and the Dutch defense (as black) seem to be related. Maybe third cousins. 

For some reason, I'm not hesitant in playing the From gambit, but frightened to play the Dutch defense.

I would say that the slav and the caro kann are like distant cousins, almost brothers and sisters!

What I mean't to say is what 2 openings are the most different. As in the Budapest and Closed Ruy, one is open with open files and diagonals while the other is full of interlocking pawn chains and such. I was also wondering if there was any prominent player now who has been able to achieve good results with these two openings