Wizkids Rules!

Lilandra: Majestrix
While Lilandra is active, your opponent must pay 2 life to use an Action Die or Global Ability.

Power Bolt: Basic Action Card
Deal 2 damage to target character die or player.

Suppose my opponent has Lilandra: Majestrix active and I use an action, such as Power Bolt: Basic Action Card. Does the payment of life (from Lilandra) happen before or after resolving Power Bolt?

In particular, what if both players are on 2 life? Thereby the damage from Power Bolt would end the game as would the loss of life from Lilandra. Could I even use Power Bolt in this case as I would go to 0 life?

Likewise, if Power Bolt were to deal enough damage to Lilandra to KO her, would her cost still need to be paid?

Suppose my opponent has Lilandra: Majestrix active and I use an action, such as Power Bolt: Basic Action Card. Does the payment of life (from Lilandra) happen before or after resolving Power Bolt?

Lilandra’s cost requirement must be paid by your opponent before any Action die ability or Global Ability is used.

In particular, what if both players are on 2 life? Thereby the damage from Power Bolt would end the game as would the loss of life from Lilandra. Could I even use Power Bolt in this case as I would go to 0 life?

In this situation, the player controlling Lilandra would win. The Power Bolt ability would not be initiated, per the following rule:

Rule 2.9.1 As soon as a player’s Life total reaches 0 or below the game ends immediately and the player with Life remaining wins. Even when an ability causing one player to reach 0 Life trigger other abilities that would subsequently put another player at 0 Life, those other abilities would not occur.

Likewise, if Power Bolt were to deal enough damage to Lilandra to KO her, would her cost still need to be paid?

Yes, because Lilandra’s cost must be paid before the Power Bolt ability is used to damage her.