Was Messi's Penalty Kick against Celta de Vigo in La Liga 2016 considered a miss, according to FIFA rules?
In Are players allowed to pass a penalty? it's established that it is possible to 'pass' a penalty kick, however does it count as a miss?
Technically football officials don't record 'misses'. Only statisticians do so. There is no definition of a 'penalty miss' in FIFA's Laws of the Game. (I'm mentioning this since you have tagged
The goalscorers in games in major tournaments (like Spanish La Liga, English Premier League, UEFA Champions League, FIFA World Cup, etc.) are recorded during the match by the match commissioner. The competition organizers then keep tally, for awards like top scorer and best player which are given at the end of the competition. In this case, the Royal Spanish Football Federation would add the goal to Luis Suarez's tally, while Lionel Messi would be credited with the assist (which most federations keep tally of as well). But again, there is no record of any penalty (or any other kind of) misses.
Statistics companies do keep track of penalty misses and various other statistics for informational purposes and I suppose this would count as a miss as mentioned by Oak in the comments to your question.
As to whether this is allowed, FIFA Laws of the Game 2015/16 state:
Law 14 - The Penalty Kick
After the players have taken positions in accordance with this Law, the referee signals for the penalty kick to be taken
The player taking the penalty kick must kick the ball forward
He must not play the ball again until it has touched another player
The ball is in play when it is kicked and moves forward
Messi and Suarez complied with all the above rules. Hence, it was a legitimate goal.