[LintMan]

I don't think the diease is curable as long as the unit is still carrying the fetish. A regeneration ring might keep it from getting more afflictions and dying, though. More effectively, though, you can give the fetishes to disease-immune units like the undead, and they are unaffected by the disease yet still produce gems. Some may regard this as an abuse, though.

One unit can indeed hold 2 fetishes and get 2 gems/turn.