The original line-up is not getting back together, ever. So let's try this:
Get the 2002 line-up back together for two weeks:
So they've got two weeks to record twelve songs:
Welcome to the Jungle
It's so Easy
Out ta Get Me
Think About You
Sweet Child O' Mine
(If you really want, they can record these four songs as bonus tracks:)
(Move to the City)
Wrap up the album, call it "Appetite for Destruction: The New Millennium", advertise it as being 2015 re-recordings with Buckethead.
This also solves the other problem. Axl won't give Harmonix/Ubisoft permission to use the old 1987 version? Fuck it, just use the 2015 version. Same shit, more guitar solos. Money in the bank.