My son will train for next season for the following facets of the game: Strength training, hitting, fielding, long toss and speed training. Assuming he does all these in one day, my question would be in what order should these exercises be done to maximize his efforts?

I would split the workout up.

You can do in two sessions in one day or alternate days.

Physical Training workout
-Speed
-Weight Training

Skill Training Session
-Long Toss
-Hitting
-Fielding