There's a saying in the Middle East:
"I against my brother; my brother and I against our cousin; my brother and my cousin and I against the world."
As much as Iranians hate the mullahs, they would turn on a dime and support them if the Saudis attacked.
That's just reality.
So the Saudis--I'm 99.99 percent sure--won't do anything overt.
The Lebanese STILL support Hezbollah. they know that their support is insane, but they won't stop.