The hippies would appear to be a pastiche of the Scooby Doo gang sans Scooby himself.
The animation style give the Stranger the appearance that he's wearing a mask. Traditionally in the comics it's more the case that his face is always obscured by shadow.
Included on the bluray release of Superman: Red Son (2020).
This is not Michael Rosenbaum's first DC role. He has previously voiced The Flash in Justice Leauge animated series and the subsequent Justice League Unlimited. Notably known for his portrayal of Lex Luthor in the T.V. series Smallville.