Only teammates within the range of influence of Imperial Mask's controller will get a token. Imperial Mask's controller doesn't get a token; that player just gets the Imperial Mask.

If Imperial Mask becomes a copy of something else after the ability triggers but before it resolves, the tokens will enter as copies of whatever the ex-Imperial Mask is now. If Imperial Mask became a copy of something else and then left the battlefield, the tokens will enter as copies of whatever it was copying when it last existed on the battlefield.

This card creates tokens that enter as enchantments, not creatures.

If Imperial Mask has left the battlefield by the time the triggered ability resolves, the tokens will still enter as copies of Imperial Mask.

Each Imperial Mask permanent is independent and affects only its controller and the opponents of its controller.