Morrison does indeed borrow things from the Silver and Golden Ages quite a bit.
He's been doing it most of his career at DC, and now he's even beginning to reference himself. In those Superman Beyond 3-D issues, when Supes ends up in Limbo where Merryman from the Inferior 5 is 'king'? That's straight out of his Animal Man run in the early 90s...
A lot of those weird, forgotten things came up in Batman because Bruce was a prisoner in his own mind courtesy of this thing called, The Lump. So while trapped in there, he came across all sorts of arcane memories including the two examples you show.