[IAmBatman]

Red Skull could still be picked off at range with that scenario. I'd argue that, for the points, in mixed play, an army of

Hulk, roborats x3, Isamu

would clock an army of

Red Skull, roborats x2, Mimring, Shiori, Marcu.

Who's going to kill Hulk there? Mimring might get a wound or two on him, but Hulk won't let Mimring play the hit and run game that works so well on others. One superleap and their engaged. Mimring can disengage every turn and shoot from afar to slow down the size of Hulk's attack, but his base attack is plenty to get past Mimring's small defensive number, and with this strategy Mimring is risking a disengagement swipe every turn.
Shiori and Marcu are going to have a hard time cracking through Hulk's defense of six.
Red Skull in this army is a figure you'd want to play back to take full advantage of his tactical abilities. But he's also the best candidate in this army to take out Hulk. Your best shot, IMO, would be to tie Hulk down with rats (though his special attack should make short order of them) and bring Skull close to try his dust of death a couple times before Hulk breaks free and demolishes him. You get that lucky high roll, awesome, game over pretty much. If not, you don't have anything left that can really take Hulk out.
I'd take my chances on that roll being 18 or lower for the two or three chances Red Skull would get.
Also, if I'm playing the Hulk army, I'm using Hulk on everyone except Red Skull (who my opponent will probably be keeping back anyway), I'm using my roborats to keep my opponent's off of Hulk, and I'm using Isamu to slip through the rat curtains and attempt to assassinate Red Skull (of which he has a decent shot, given Red Skull's frailty, IMO).
Mimring would be annoying against My rats with his fireline, but, like I said, Hulk could make short order of the red dragon.
Hulk with his base attack averages two skulls per attack. This increases as he's injured. Mimring and Red Skull both have defense of 3, meaning an average of one shield at a time. On the other hand, the highest of their attacks, Mimring's at 4, averages only 2 skulls an attack, which is the same as the number of shields Hulk averages.
Neither one is going to live long engaged with Hulk.