Faery Queens & Underwater Artillery

[incognito]

Two very separate questions:

First, I have finally managed to summon a faery queen for the heal ability in a SP game I am playing. I wanted to complement that faery queen with tartarians, leveraging the healing ability to remove their afflictions, before I GoR them. To maximize chances of healing, should I do this in a province with fewer units or does it matter? Would having the chalice improve my chances of healing the tartarians? Anyone know the math of two heal effects? I am also curious how these compare with Arco's natural heal ability.

Second question, in the same game one of my underwater castles is under seige by a mound of Ermorian undead. I wanted to experiment with a long range damage spell, but did not know any that would work underwater.. Although less relevant for this particular game, are any of these spells anonymous? It seems that the lack of long range army-killing spells that work underwater is a big advantage to Ry'leh & Atlantis.