Convoke (Your creatures can help cast this spell. Each creature you tap while casting this spell pays for {1} or one mana of that creature's color.)
Destroy target planeswalker that was activated this turn or tapped creature.
A planeswalker was “activated” during a turn if one of its abilities was activated that turn. This includes its loyalty abilities and any other activated abilities it may have. That ability may still be on the stack, or it could have resolved, failed to resolve, been countered, or have been removed from the stack some other way.
Emblems are separate from the planeswalkers you got them from. Activating an ability of an emblem doesn’t cause any planeswalker to be “activated.”
Once an ability of a planeswalker is activated, it doesn’t matter if the planeswalker loses that ability. That planeswalker has still been “activated” that turn.