My question is,
2.) Also, I need to be able to add custom behavior to the animations based on my game logic. For example, one of the UI components that I need is the health bar. The bar will increase/decrease based on current health of the player. The UI created by the designer for the health bar is a MovieClip that shows the health bar being animated from 0 health to max health. Whats the best way to integrate this into my existing game logic code? Is it better to work with MovieClip object, or is it better to ask the designer to give me a static health bar UI, and I'll just program the animation of the health bar myself using createjs?
What you're trying to use Canvas mode for is really, really not what it was designed for. In the long run it would probably be easier for you to integrate your game code into the Animate IDE, or to have your collaborator just give you raw graphics.