It has been discussed many times on this forum that Apple store employees have no more "insider" knowledge than anyone else. So ... I tend to doubt any significance from a wink given from an Apple store employee to your friend.
But, if I were to venture a guess at what the next iMac will have (whenever it comes out), I would have to say:
1) I think they'll try to squeeze one more G4 revision out of the iMac (I hope I'm wrong) and bump it to 1.42ghz. The 13 micron G5 used in the current towers seems wayyy to hot and uses way too much energy for the iMac form factor (look at the massive cooling apparatus in the G5 tower). The newest 9 micron G5 (as in the Xserve) use about half the energy (24.5 watts @ 2.0 ghz vs 51 watts @ 2.0 ghz for the 13 micron G5) .. so I think the iMac will have to use it. BUT, with Xserves just announced and new towers pending (or so everyone seems to think), I would imagine Apple wouldn't want to risk having three product lines needing the same new chip all at once .... if there were any supply or quality problems, it could cause sales of 3 different products to come screeching to a halt all at once. NOT GOOD.
Again, I hope I'm wrong, but I think the next iMac will stay with the G4 if it were to come out tomorrow. Now ... if they don't update the iMac for another few months, maybe the next rev will go straight to G5.
Of course, take this with 4 grains of salt as my knowledge of what Apple's going to do next is about a reliable as a wink from an Apple store employee
Other specs you mentioned seem pretty reasonable ... incremental upgrades.