Ash's ultimate ability, Assert Dominance doesn't give her CC immunity at all or Damage immunity until she lands. You can use Void Grip to keep Ash in the air after her leap and let your team kill her before the ult lands.
Rucus is a pain if you're the only one attacking him but if you have movement speed, use explosive flask and use weightless to evade him then its easier to counter as long as you move like a bat out of hell; only this one has a potion launcher.
Unlike certain champions, Pip's damage is the same from wherever you fire from or where you hit. Remember to keep distance and practice getting used to the arc of his attacks.