one issue this season was the Jays having Moreno sitting on the bench to end the season. He their best prospect asset (above average MLB catcher) and they would not use him in games and apparently not in trades either.
Next season this needs to be rectified, 3 players for 1.5 spots (C and part time DH)
I would choose to move Kirk, my opinion without knowing the facts about relative trade value. My thought is that Moreno has the highest trade value because he is the youngest and has the highest ceiling. Kirk would have 2nd value because of age/control.
it becomes asset management and moving one is important to improve other areas of the roster. The next discussion would be where you prioritize you areas to improve. Contenders don't have players like Tapia getting 500 AB in a season. so i would like to add a CF. If you move Springer to RF you prob also are going to move either Hernandez or Gurriel otherwise you have a log jam with 4 full time OF (Gurriel, Springer, Hernandez, new CF)
so off season i'd trade Kirk and Hernandez/Gurriel to improve your team. you'd add a full time CF and hopefully a higher end Starting pitcher in that scenario.
Relief pitching can be added through Pearson, Zulueta and Free agency