Flying, vigilance, haste
Whenever Aurelia, the Warleader attacks for the first time each turn, untap all creatures you control. After this phase, there is an additional combat phase.
When a permanent leaves the battle and re-enters it becomes a whole new permanent with no knowledge of his previous existence
Because the Aurelia, the Warleader that would ETB from Cloudshift would be treated as a new permanent, its ability will trigger if you attack with it. Everything will play out like you want it to.
Do note that you have to cast Cloudshift before the second Declare Attackers step, though.