Response to RFE for EB1- Alien with Extraordinary Abilities Questions

If there's anyone out there that can give me some advice it would be much appreciated. My boyfriend, a prof. dancer from South Africa, has applied for a green card based on the fact that he's an extaordinary alien due to his professional dancing abilities. EB1-A or B I think it's called officially (sorry I've been overwhelmed by this entire process) He was on BBC's "Dancing with the Stars" for two seasons and won numerous natinoal awards back in South Africa. He and his lawyer filed his petition for the green card a few months ago, and shortly afterwards he received a temporary work authorization card that would last until a decision was made. However, About two months ago, we received an RFE-request for further evidence- asking for furthersupport to his claim.

THe USCIS agent who reviewed hsi case was rather critical and explained that just because he was a celebrity back in south africa doesn't mean he's kept up a level of sustained success here, etc. The RFE basically indicated that he needed 3/10 criteria fulfilled and that the information provided didn't correlate with that. His lawyer did a terrible job putting the package together the first time, I have to admit, so this time he made sure everything was there. My boyfriend spent several weeks compiling further evidence and has answered the RFE completely, and we got a letter last week saying that we will receive a response sometime in the sixty days . The USCIS service center that is processing his file is in Mesquite, TX. His lawyer says that he has a pretty good chance, but that nothing is for certain in these extraordinary alien green card cases.

I have a few questions I was hoping someone could answer.

About how long do you think it will be before we hear something from the USCIS? Are most RFE's approved or rejected? Will their answer only be a "denial" or "approval" or could we possibly get another RFE?
In the event that his application is denied, will his work authorization be terminated immediately? He JUST started a new job (will be still training for the next few months) working for an airline. We are counting on his green card coming through or else we don't know what to do. If his request is denied- will there be some way for him to get a temporary work VISA through his employer? or will he be out of luck entirely? He is prepared to quit his job if he has to, but we would like to keep him in the USA>

This is such a frustrating process :( If anybody has any ideas or suggestions, let me know. I'm sorry that I'm not as knowledgable in this area so I may have been confusing in my analysis above.