The Rebel enters the battlefield as a 2/2 creature, then the Equipment becomes attached to it. Abilities that trigger when a creature enters the battlefield see that a 2/2 creature entered the battlefield.

If the Rebel is destroyed, the Equipment stays on the battlefield. Similarly, you may pay its equip cost to move it from the Rebel token to another creature you control.

If the ability causes two Rebel tokens to be created (due to an effect such as that of Mondrak, Glory Dominus), the Equipment becomes attached to only one of them.