Wizkids Rules!

Tyrannosaurus Zombie: Paragon Undead
While Tyrannosaurus Zombie is active, at the start of your turn, field an NPC die from your Used Pile.
While Tyrannosaurus Zombie is active, your NPC character dice are considered 2A and 2D Zombies (only their name and A and D values change).

To what extent does changing an NPC character die's name to Zombie have on other game effects? Do they still count as an NPC/Sidekick character die?

Goliath Fighter: Lesser Zhentarim
Experience
While Goliath Fighter is active, at the end of each turn, if 2 or more opposing NPC character dice were KO'd, Goliath Fighter gains an Experience token.

For instance, if two of these Zombie character dice (formerly NPC) were KO'd, would an opposing Goliath Fighter still gain an Experience token?

S.W.O.R.D. Agent: Eyes Beyond Earth
Ally
S.W.O.R.D. Agent gets +1D for every Sidekick die in either player's Field Zone.

Further, how does this affect characters in other sets with the Ally keyword? Since an Ally becomes a sidekick in the field, they should now always be 2A/2D and be renamed Zombie. Since they have a new name, does that replace their name in their own textbox or would their abilities become defunct?

To what extent does changing an NPC character die's name to Zombie have on other game effects? Do they still count as an NPC/Sidekick character die?

The intent of Tyrannosaurus Zombie’s ability is to change a Sidekick Character die into a Zombie character die with 2A and 2D values, i.e. replacing the die’s name and A/D values. An NPC (Sidekick) Character die no longer counts as such a die while Tyrannosaurus Zombie is active and any abilities that affect NPC (Sidekick) Character dice would not affect these Zombie character dice. However, this die is still a level 1 character die with a 0 purchase cost for other applicable abilities.

For instance, if two of these Zombie character dice (formerly NPC) were KO'd, would an opposing Goliath Fighter still gain an Experience token?

No.

Further, how does this affect characters in other sets with the Ally keyword? Since an Ally becomes a sidekick in the field, they should now always be 2A/2D and be renamed Zombie. Since they have a new name, does that replace their name in their own textbox or would their abilities become defunct?

When a Character die with the Ally keyword is fielded, it is now considered a Sidekick (NPC) Character die. If Tyrannosaurus Zombie is active, this die will now be considered a Zombie character die with 2A/2D values – replacing the Ally die’s name with “Zombie” and its A/D values as applicable. However this die, based on what character face is showing, would retain its level, fielding cost, burst ability (if applicable), and also its energy type, affiliation, and purchase cost for abilities that affect these attributes.

Pertaining to S.W.O.R.D. Agent’s ability, the die would now be a “Zombie” and can still get +1D for every Sidekick Character die in a Field Zone, but the ability would not count any S.W.O.R.D. Agent (or other Ally) dice controlled by a player who has an active Tyrannosaurus Zombie die because they are no longer Sidekick Character dice.


The above ruling also applies to NPC (Sidekick) Character dice affected by the ability (see below) of Kir Sabal: Aarakocra Monastery. The NPC dice moved into the Field Zone are no longer considered NPC (Sidekick) Character dice but Aarakocra character dice with 3A/3D values.

Move up to 2 NPC dice from your Used Pile to the Field Zone on their [?] side. They are considered 3A and 3D Aarakocra character dice. KO them at the end of the turn.