Um, given the same Ambush situation, the Warblade maybe has 120hp (more than average for a Warblade with Con 20), and let's assume the Ice Devil loses initiative. Now, the Ice Devil still gets his surprise round, so he activates Fear Aura and blasts the whole group with Cone of Cold, the Warblade auto-succeeds his Will save, the others, having no use for Wisdom, have maybe a +9 modifier to will saves and fail 60% of the time. Three of the four characters probably fails their saves against Cone of Cold and take an average of 46 damage, but let's give them Cold Resist 20 given that they've prepared somewhat against the Plane of Ice (they don't have Resist Energy available because it isn't on their casters' lists). So probably one of the party is Frightened and the others are damaged but not significantly. The Warblade, not needing to charge, full attacks with his +2 Greatsword with his attack bonuses of +20/+15/+10/+5, impressive for 10th level, but hardly statistics indicative of slaying the Ice Devil in one round (not against it's AC 32). Let's say the Binder ran away from the Fear Aura. Dread Necromancer probably has a small horde of undead assault the Ice Devil, but between its DR 10/good and Regeneration 5, I'd wager the Ice Devil is barely harmed, the Necromancer still has his turn and if he can hit he'll two round the Devil with Shivering Touch, but then again, his attack roll is +5 vs Touch AC 14.
Ice Devil goes and flies in the air provoking attacks from the Warblade and all of the Undead, but even those that hit have to deal him more than 15 damage to scratch him. Let's say between the Warblade and the Undead that went before him, he's taken 30 damage from attacks and attacks of opportunity. But now he's in the air, he still has over 100hp, he's safe from the Warblade and the Undead. Honestly he could probably just rain Cones of Cold on the party from here until they died, because the casters' spell penetration checks are going to be 1d20+10 vs 25, and I can't think of anything hugely useful for the Beguiler to do to the Devil anyway. Or by "intelligent tier 3 group" did you mean they spent inordinate amounts of GP to get immunity to cold before they went to the Plane of Ice? Because if that's the case the Ice Devil can certainly be played a bit more intelligently too, and regardless of how it's played at least one character will almost certainly be killed. More if, while concealed in the snow, the Ice Devil was able to successfully summon 4~5 Bone Devils.