I admit the thought of Rat Ogres throwing bombs at you Donkey Kong style has something amusing
Hard to say what they will come up with. It could be anything from existing monster/special abilities to existing hero abilities or something completely new. Imagine a Shade or Assassin Rat Ogre, going invisible on you. Or a fire breathing Chaos Spawn. Or maybe some simpler attributes.
I would be very surprised about another weapon pack at this point. It is getting increasingly more difficult to find non-used lore weapons and to make them feel unique. Due to the existing pool they either have to invent some completely new niche (SotT Staff) or make it overpowered (the last weapon pack).
I remember this to be a reocurring theme. I think the outfit is possible. The pistols … not.