Where exactly does this "confirmation" come from ?
When another block on the network confirms it. That only shows up when BTC Guild just found a block and no new block on the network has built off it (IE: We don't know if it's going to be orphaned or not yet).
Yep. The pool no longer pays for orphans, but it doesn't require a 100-120 confirmation wait. The likelihood of a block getting orphaned after it is confirmed is extremely low, to the point it just doesn't seem worth delaying the application of rewards to wait for even more confirmations.
In the past, oh lets say 6 months, how many orphans has BTCGuild seen ?