I agree that the white light was another time jump (possibly caused by the explosion), but I'm not sure about them returning to 2007. I heard Ben (can't think of his real name) doing an interview on a local Orlando station (by phone) and when the DJ asked him if the group in 1977 would get back to 2007, he said, "I'm not sure you should be thinking that way." Of course, he wouldn't elaborate on it any further.
Doesn't mean they won't all get back to the same time, but just not to the present time that they left. I guess... If the explosion worked as planned, then they would return to Flight 815's time, not the actual present. Jeez, I feel like I'm in a time warp myself.
Ben also mentioned in the interview that he and his wife discussed the issues of time travel and Faraday's Mom sending him back in time to be shot by her, and the whole idea that what's done is done... but what if it's not done yet, etc. etc. and he said they were totally confused too. It was funny.