Hmm... That is a shame.
For the healing spell, my alternative would be to have the healing be based on the percentage of unit's hit points. Something like:
"Calc = UnitStat_HitPoints * 0.75 - CurrentHealth; Value = Calc / 3". This would heal about 25% of a unit's health if it is close to zero, and about 15% of current health if it is at 30% health.
Of course, the value would result in a negative value if the unit is over 75% hitpoints, but hopefully the AI will be smart enough not to use it under those circumstances.
For the harming spell, the approach isn't really possible, since I definitely don't want to have it adding hitpoints for enemies at low HP.
For issue 3, I wouldn't want to have the technology being associated with the faction. This was more intended to support greater differentiation between sovereign backgrounds, and allow them to provide a delayed bonus for the late-game. The intent would be that the background is not limited to a particular faction.