Delney, Streetwise Lookout

Once an ability of a creature you control has triggered, reducing its power to 2 or less won't cause that ability to trigger an additional time. Similarly, once an ability of a creature you control with power 2 or less has triggered an additional time due to Delney, Streetwise Lookout's last ability, increasing its power to 3 or greater won't remove that additional triggered ability from the stack.

Abilities that apply "when [this creature] is turned face up" will trigger an additional time only if that creature's power is 2 or less once it has been turned face up.

In some cases involving linked abilities, an ability requires information about "the exiled card." When this happens, the ability gets multiple answers. If these answers are being used to determine the value of a variable, the sum is used. For example, if Elite Arcanist's enters-the-battlefield ability triggers twice, two cards are exiled. The value of X in the activation cost of Elite Arcanist's other ability is the sum of the two cards' mana values. As the ability resolves, you create copies of both cards and can cast none, one, or both of the copies in any order.