This offer (or something very much like it) was agreed to in principle by both parties.
(Possibly at this point, Gainey trades Huet, thinking that he is going to get Hedberg back with 90% certainty. Or maybe he'd already decided.)
Then Atlanta drags its feet and do not follow through with the agreed-upon trade, continuing to entertain offers. The Habs are still frontrunners however.
The Penguins swoop in at the last minute and make the Armstrong/Christensen/Esposito/1st offer for Hossa and Dupuis.
Atlanta decides that this is a better deal than the Habs', and turns around and asks Gainey to improve their offer -- possibly asking for Chris Higgins at that point. Hence asking for three roster players plus a draft pick.
Gainey says "no way". Or makes some counter-offer.