I don't know if the charcoal will absorb the herbs or not, but the people who sold you the charcoal might know. It is a good idea to rotate remedies anyway.
And regarding the question of how long to wait before you begin taking humaworm, that is a great question for Humaworm. It also depends on what ails you. The life cycle of Ascaris is longer than pinworms. If you have them both, it is tricky.
Can never go wrong deworming on full moons, as difficult as it may be.