Here's the newest scoop on Grey's Anatomy from Michael Ausiello at TVGuide.com:

Izzie and George — noooooooooooooooooo!

My thoughts exactly. BTW, don't forget to check out my urgent news bulletin regarding tomorrow night's Grey's. Your life depends on it.
My birthday was last Friday, just like your BFF Lauren Graham! That should be worth some serious Grey's scoop.

Lucky for you, I just received a fresh batch of intel regarding the enhanced two-hour May-sweeps episode of Grey's Anatomy with a potential for afterlife (aka the spin-off). According to multiple unnamed spies who (lucky for us) can't keep their traps shut, Addison comes to the conclusion that (Spoiler alert) McSteamy is about a decade away from becoming father material, and hightails it to Los Angeles to meet with one of the world's foremost fertility experts. Mrs. Egg Harvester is also one of Addison's BFFs and the owner of a state-of-the-art wellness center, which just so happens to be looking for a neonatal specialist. I think you can figure out the rest.
OK, totally hated the George-Izzie hookup on Grey's last week. That was the last thing I thought was true from your list of twists. I had money on Burke's transfer!

Funny thing is, one of the "false" plots twists nearly turned out to be true — and it still might! I got a questionable tip about two weeks ago that (Potential spoiler alert) Callie was pregnant, and Grey's was planning to set up a whole "Who's the daddy?" story with George and McSteamy. But now it looks like that was another Shonda Rhimes-tested and -approved foiler.
So George and Izzie actually happened on Grey's Anatomy. I guess you gave us fair warning. Now can you please assure us that it was a one-time drunken mistake and it won't be happening again?

I really wish I could. But I can't.
I heard on the radio that Lisa Kudrow may also join the Grey's spin-off. Have you heard anything about this?

Not true. Lisa was up for one of the primary roles — Amy Brenneman's part, perhaps? — but apparently a return to TV prompted this reaction from her: "I don't want to see that!" (Never gets old.)