What should be defined as an en passant checkmate? Is there a general consensus among composers, players, and/or organizations for what exactly defines an en passant checkmate, and is there any history  to it?
As far as I know, there are two possibilities to define it by.

The pawn captures, moving to deliver a discovered check that results in checkmate.

The pawn captures, and the pawn itself checkmates.
After some research I could not find  any "official" definition by a chess association/federation. This doesn't really surprise me, as there really is no need for a definition of "e.p. checkmate" to ensure correct play.

However the general internet consensus on the usage of the term seems to agree on the following requirements:


The game has to end with checkmate.
The last move has to be played en passant.


An exemplary notated move would be "29... cxd e.p. #" (although notating e.p. is optional under the FIDE laws of chess (C.9)) - regardless if the pawn capturing delivers check or not. The Wikipedia examples follow this definition.

As there is no opinion by a regulatory instance about this topic, it seems to be up to you to make up your mind on this topic or bringing it to the attention of said regulatory instance. I am taking the "democratic" approach with the above definition.