My Mold men will possess tremorsense, since they will not be able to speak. They will have regeneration (except to fire and acid), and Damage resistance 20/ slashing or Piercing. They will also possess the ability to create spawn, though it will be time consuming.
1. What should their challenge rating be, assuming they are based on having 1 Hd?
2. Should the resist elect., cold, magic, etc.?
3. Are there any other things you wonder about that I could clarify?
edit: I have decided to add Water sensitivity in order to offset some of this. When immersed in water, or in conditions of moderate to heavy rain or snow, their DR drops to 10.