Ability: Poison Point or Liquid Ooze
Reasoning: Poison Point makes it a better switch in to physical attackers because of its high base def. (120BST) Liquid Ooze so it can switch in to Leech Seed/Drain Punch users which in my opinion are very common on this server and is a strat that i use myself.

Ability: Reckless
Rapidash its abilities are rather on the side of unviable, due to rapidash having access to Double-Edge,Wild Charge and Flare Blitz giving it reckless or even rock head (This latter one seems really weird tho) would definetly boost Rapidash in Power