Midnight Mayhem affects only Gremlins you control at the time it resolves, including the Gremlin tokens it creates. Gremlins you begin to control later in the turn won't gain menace, lifelink, or haste.
Create three 1/1 red Gremlin creature tokens. Gremlins you control gain menace, lifelink, and haste until end of turn. (A creature with menace can't be blocked except by two or more creatures.)
