1. Orcs may buy clubs for 3gc. The lack of them in their equipment last was an oversight and they may now officially use clubs (see Mordheim Rules Review).
2. Orcs may wear Light armour, shield and hammer (see their equipment list). Gromril and Ithilmar armours are considered to be special kinds of heavy armour and can thus only be used by models who have "heavy armour" in their equipment list. This means that Orcs may only use light armour but not heavy, Ithilmar or Gromril armour. Goblins e.g. never wear any sort of armour (even if you had 20 pieces of Gromril armour in your storage). This issue has been answered in an official Mordheim FAQ (see Mordheim.com).
This should clear things up.