About the shading part, for now you might need appropriate sprites displaying the enemy in the appropriate color, there's no real way to change the hue of sprites (js limitation for now).
For the encapsulate part, I guess you need to set the bubble position to the enemie's position (or the inverse) when they collide each other, and "pause" the behaviors that make the enemy and bubble move.
It depends on how you setted up things so far.