There is only one person I know for certain is not the choice. The other six...who knows? :x
Gotta be Roddy, right? Donati too, since there's that scheduling conflict with him and DT. I'd say Minnemann's pretty unlikely as well. The other four, I don't really know.
Complete speculation on my part here, but one thing I found interesting: Petrucci seems to be the guy giving lots of feedback on the auditions (he was the one who responded to Mangini, discussed a lot about what they were looking for, etc.), and yet, we saw in the preview that it's LaBrie who ultimately "welcomes the drummer to the family."
That leads me to believe the drummer is somebody who's closest connection to the band is with JLB, which narrows it to Mangini, and, of course, our good friend Wildoer.
Not that my logic is airtight, but along with all the Mangini speculation that's already been done, and the fact that Wildoer's posting here now...
There's also the whole primacy and latency effect thing--since Mangini auditioned first and Wildoer last, that means those two were most likely to make the biggest impressions, all else equal, since people tend to remember what they saw first and last the most.
Right now, I'd rank it like this, from most to least likely.
Mangini
Wildoer
Priester
Lang
Minnemann
Donati
Roddy
In 40-60 minutes, my mind will likely change, I'm sure.