[Snake]

iirc Immobilize/Frozen doesn't really affect Gain Air or Burn Up because it's only intended to stop movement skills. Those just grant you Airborne.

Riser isn't a movement skill at all, if that's what I'm thinking it is. (The one that throws two feathers and makes someone go airborne, isn't it?)

Pierce Linker and Falcon Strike, if they grant Mirage Scale's effects, are then movement skills and should be affected. That one is correct.

Same goes for Jhunn's skill (Does it grant Mirage Scale's effects? If so, then it should be a movement skill). Although that's a bit of a chin rub, given the skill is a burst of fire making you blast forward, mechanically speaking it's the Youkai giving you a boost, not you moving.