I think eragon and arya steal the egg

thats plausable, but i think they either wont have to and will just grab it once galby dies, or the egg is on the ship that is coming in to the harbor at the end of brisingr, and the varden will take it and kill all of the "laughing soldiers" that would then be on the ship, along with all of those magic users that would be on the ship as well, protecting the egg.

I think Roran will lead a campain into Uru'bane and steal it during the battle to take over Uru'bane.

I think Murtagh will change his true name and let Eragon into the place were the egg is kept.

Galby can force Murtagh to say oaths that don't require Murtagh's true name to stay the same to function. ie: the kind of oaths that Eragon forces Sloan to say.

I'm not sure if Galby made Murtagh swear any oaths even though he probably did. Galby wouldn't need him to swear any oaths if he could control him with his true name.

Still why wouldn't Galby make Murtagh swear oathes there's not really any downsides....

I don't believe that CP would just leave Murtagh being evil. He has to break free of Galby's spells and oaths.

That's not a reason for Galby not to make Murtagh swear oaths that require his true name. The only reason that I can think of is that Galby has missed the obvious point because he's crazy. Remember Brom says Galby has gaps in his reasoning that other people won't have.

But what kind of gaps.

No-one knows including Galby otherwise he would fix them. It's gonna be a total surprise.

One of these gaps will probably enable Eragon to kill him.