Two types is okay as long as they arent used for the same thing. However, something as specific (and with a 4x weak to fire) such as foreetress and scizor should be avoided preferrably, if you looking for a spiker why not look into skarmory (even if you have a flying type it wont be steel and therefore it wont share weaknesses as much as scizor and fore)
Skarmory@Leftovers
Nature: Impish
Ability: Keen Eye
---Drill Peck
---Spikes
---Whirlwind
---Roost
hope that helps