Too late. The 5th Circuit already has issued its Order, and the only body with the power to reverse that is the Supreme Court.
I don't believe that is the case. There are cases about the ETS in every Circuit Appeals Court. They will be consolidated (a Circuit will be selected from which to proceed) by means of a lottery in the upcoming week.
No. This is just a temporary stay. It is not a ruling on the merits. That goes to the lottery on the 16th. This stay does not go the supreme court and will not be overturned because it expires once the circuit court gives its final ruling.