Happy days!
I've implemented the functionality for the colours of the physics objects based on their type and activity state (based on bullet collisionFlag and activationState).
Some feedback about more appropiate colours, or whether the current choice is absolutely fine would be grand 
If you're not familiar with bullet physics, my basic description would be
- Static: physics does not move them, nor do you.
- Kinematic: physics does not move them, you can directly (translate / rotate).
- Character: physics moves them, you can indirectly (walk() method).
- Dynamic: physics moves them, you do not.
The categories and current colours are:
- Static