Yes, it does look necessary.
As Taylor said, CT and reverse sneezing are not related. Intubation can increase reverse sneezing immeduately following extubation. They don't jam it down.
It is actually a great safety measure to intubate (besides being necessary for a proper dental).
Make sure IV fluids are ran during the procedure.
Pre-op labs include a CBC and chemistry at a minimum. While almost always considered unnecessary for healthy dogs, if you want to be extremely cautious (and spend a ton of money) you can get a urinalysis, bile acid test, chest xray, and EKG.