I'll admit that I did not see it, so cannot judge if it was late or not, or how severe it was. Often during scrums in front of the net that result in a goal a player may not realize the puck has gone in, or that the play is over, so I'd give them the benefit of the doubt
Do not recall seeing anyone laying on the ice after the goal was scored. All I saw was a celebration. If there was indeed a player laying on the ice hurt after the game, then yes, by all means it should be discussed/dealt with by the refs/discipline committee if a foul was committed.
I recall in a tournament final many years ago, a player scoring an empty netter and then getting cross checked into the cross bar by the trailing player as time expired. In that case the offending player got 8 games and the player cross checked into the cross bar was finished for the season with a concussion, so it was dealt with properly. I would hope that if an infraction is severe enough, the refs would deal with it.
My point in the previous post was more about. You won, celebrate that fact, rather than rubbing it in to a team that gave it their all in a great game and lost.
