The Arbiter rules for black. Black wins.
Correct. The relevant article is section 4.6 of the FIDE laws of chess, which stipulates that a move is completed when the moving player's hand releases the piece on its destination square. Thus, White's claim that the Black Pawn "never reached d5 to block the check" is false.
The Arbiter rules for black. Black wins. The en passant doesn’t remove blacks’s checkmate and therefore cannot be a legal move.