How, exactly, does the Ki Healing “can only repair up to half the damage” rule combine with other sources of healing?

The behavior of Ki Healing in combination with other sources of healing does not seem to be well-explained, and I would like to know if there are any rules or rulings about its interactions with other sources of healing and/or alterations to health, such as those listed below.

  1. A healing spell that restores points of HP.
  2. A healing spell that restores percentages of HP.
  3. Other sources of Ki Healing.
  4. Natural regeneration (especially high values thereof). (also consider cases in which a character has taken some damage, regenerated it fully, and then takes more damage later.)
  5. Other sources of elevated regeneration.
  6. Effects that increase/decrease your MHP.
  7. Returning to 0 HP from negative HP through Between Life and Death rules.

Basically, this question is asking “how does ‘half the damage’ count damage”, but there are a lot of things that I think can interact with that.