You have my support on fremennik imbued rings and the implementation. Also Kaarel's idea of dropping a normal fremennik ring should be applied.
Healing effect is too much for multi-spells imo. Either a lower rate is applied on magic multi-spells or we should think of something else.
As far as RoW is concerned, I don't know what to think. I wouldn't mind the effect, but it being degradable with so low charges, doesn't make much sense. No-one would keep getting scrolls for these from CW, they'd just become dead content after the first week (max). We could just apply the effect to a normal enchanted dragonstone ring (RoW), imbue scrolls are not required for this one.