EDIT: Sorry, didn't see the previous post. Consider this just further explanation!
If you have the paid version, families sound like the way to go. If not,
you could have one character sprite with 3 times the animations, and swap the animations based on both the character number and the activity the character is performing. So the run animation for character 1 might be: run_1, while the run animation for character 2 might be run_2, and for character 3 it would be run_3. The idle animations would be idle_1, idle_2, idle_3, etc. Easy to implement since you'd just append the character number on to the end of the animation each time you switch animations.