Assuming playerprojectiles is the bullet hitting the enemy, the event should be Playerprojectiles on collision with enemy, so you can pick the projectile, then destroy it. That should also fix the hp problems as projectile on collision with enemy will pick that enemy and subtract damage.
Although family logic can be used to reduce some code such as 'create healthbar for red' 'create healthbar for white' etc, you can still split out some code to define things for different types. To do this, create a family instance variable 'type' and then you can assign all stats to red type and all stats to white type on created. So if type=white it will have the appropriate health.