This disc will be available in the US September 14 2010, and its creation is reported to be "supervised by Fincher". So considering the long list of perfect DVD releases of Fincher's films, I am sure this will come out great.
As for Bonus Features: As far as I can tell the commentary tracks will be the exact same ones, that previously were on the DVD Special Edition. Of course you can argue, everything that was to be said, already has been said. But personally, I would have appreciated new features as an additional tickle to buy this thing.
The Special Edition of "Chinatown" was amazing, for it had Fincher comment on the film, and I wish they would have come up with something original of that sort. "Se7en" is clearly a milestone in its genre, and I wish we could have heard a new wave of directors talk about it the way Fincher did on "Chinatown".
So it seems it will be a 1:1 version of the DVD. But hopefully at least they do a decent new 1080p transfer and not try ripping us off with an unworthy upscaling.
Here's the details: