DrunkenMage
Intoxicated Arch-Mage
and a unified Skyrim will be what the Thalmor fear. Do not forget, they do not want a stormcloak victory either. If they wanted to weaken the Empire, they would not want the war to go on like it is. They want the War to go on, because a unified Nord people would kill them all.
No. The Thalmor want to avoid a Stormcloak victory, so they carefully manage indirect aid to the Stormcloaks. An Imperial victory harms their overall position.
The Thalmor want the war to go on like it does, because it weakens the Empire, it weakens Skyrim. Though perhaps you should explain why you believe a bunch of poorly trained Stormcloaks who can't reach the Aldmeri Dominion, are what the Thalmor fear.
Plus, I doubt Ulfric waited until the legions went south. this has been going on long before Ulfric became Jarl of Windhelm. He just united the rebels.
Ulfric Stormcloak is the rebellion, it didn't start until the death of High King Torygg a little while after the Moot named him High King. The rebellion itself didn't happen until the death of Torygg, while the birthplace of the rebellion was the Markarth Incident.
"Ulfric founded the Stormcloaks years ago, as a sort of private army to advance his ambitions. He's always used the ban on the worship of Talos to stir people up against the Empire. He never succeeded in getting much support, so a few months ago he murdered the High King! That got the Empire's attention."
He wasn't getting much support over the Talos ban, until he killed the High King as a message to the other Jarls. Torygg was just a symbol, killed because Ulfric could do it.
I don't believe you know what you're on about though, Ulfric united the rebels? Ulfric started the rebellion.