Three scenarios, each one Fear of Winter is in play, and opponent has no influence.
1. Opponent plays Catelyn Stark (LOW) from hand. I play Seasick to cancel the triggered effect. Can I cancel Cat's ability? Does Cat end up in play?
2. Opponent brings Meera Reed out of shadows, using their last gold. I play Seasick to cancel the triggered effect. Can I cancel Meera's ability of blanking? Does Meera end up in play?
3. Opponent puts Bloodrider into play to cancel my character ability. I play Seasick to cancel the triggered effect. Can I cancel Bloodrider''s ability of cancelling my character ability? Does Bloodrider end up in play?
Catelyn: Challenges: Put Catelyn Stark into play from your hand, knelt as a defender during an or challenge initiated against you. At the end of the phase, if Catelyn Stark is still in play, return her to your hand.
Meera Reed: Any Phase: Bring Meera Reed out of Shadows and into play by paying the rest of her gold cost. Then choose 1 non-plot card (2 instead if it is Winter) and treat its printed text box as if it were blank until end of the phase.
Bloodrider: Response: Kneel 2 influence and put Bloodrider into play from your hand to cancel the effects of a character ability just triggered.
Seasick: Response: Cancel a triggered effect unless its controller kneels 1 influence.