TYBALD, MAESTER OF THE DREADFORT: DECEITFUL ENVOY

Can Tybald target a zone that is already occupied by another NCU?

No.

Tybald vs Olenna Tyrell. Tybald declares his ability designating a zone when Olenna activates. When she claims a zone and chooses him as the target of Pulling Weeds, removing his abilities, does that prevent him from resolving the rest of the effect?

No. The ability has been resolved already and will remain in play. See the Petyr Baelish FAQ on page 7 of the CMON FAQ about abilities being lost after declaring and resolving them.

If I have an effect that references a point in the turn, such as "at the end of the/this turn" while in the start of round sequence. What happens? If I use Tybald's ability for example during an opponent's careless Aggression NCU activation, what happens if they don't claim the zone Tybald designates?

This turn means this turn. If you are not in a turn, there is not a 'this turn' for the trigger to reference, so the ability does not get a trigger based on that. Tybald will not claim the zone in this example.

TYBALD, MAESTER OF THE DREADFORT: DECEITFUL ENVOY

Can Tybald target a zone that is already occupied by another NCU?​

Tybald vs Olenna Tyrell. Tybald declares his ability designating a zone when Olenna activates. When she claims a zone and chooses him as the target of Pulling Weeds, removing his abilities, does that prevent him from resolving the rest of the effect?​

Can Tybald target a zone that is already occupied by another NCU?

Tybald vs Olenna Tyrell. Tybald declares his ability designating a zone when Olenna activates. When she claims a zone and chooses him as the target of Pulling Weeds, removing his abilities, does that prevent him from resolving the rest of the effect?