Unless Axl's material that has been recorded, is the ownership of UMG as a GN'R production, I don't see why Axl couldn't reunite, and still release the CD sessions as solo albums, even as the reunion went on. Then when GN'R take a break from touring, like every other musician in the world, Axl could do some club shows to promote his albums, no different than Slash, Duff & Izzy would be doing elsewhere.

Sounds like a plan to me.

Then when they get comfortable enough, maybe they could collaborate on future albums as Guns N' Roses.

There's really no pressure involved artistically in a reunion. They all have solo outlets (with fans), and are marketable. Anything Axl wants to try, that isn't clicking with the rest of the band, he could always take full-throttle on his solo work. All of them have solo outlets, so nobody is going to sit back and judge either other, saying "you're not dedicated enough to GN'R". It's a new day. Axl's obviously not going to be an asshole (in 2008) to anyone in the band, who does solo projects. He's not that much of a nazi. Unlike James Hetfield, that for some reason decided to throw a perfectly fine bass player out of his band, just because he decided to do something in the down time.