7-inch thick adamantium? If it were a "wall", or similar, most of the characters listed would at least eventually be able to dent it, or if it were in a "cell-bar" form, bend it enough to get free.
However, if they are encased directly, as in physically around their bodies (as implied by the "like statues" part), then I don't think any of them can break free, as 7-inch thick encasement of such a material would be beyond the scope of any of their strengths -- they'd need at least general freedom of body to truly effect their greatest expressions of strength needed to damage/harm such a barrier.
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Side-topic: Generally, He-Man is definitely on the lower end (*relatively*) of the list above; his generally quantifiable greatest feat of strength was lifting Castle GraySkull, and that was with great strain; he was only able to throw it/propel it across the sky/horizon by The Sorceress channeling all of the castle's power through him, effectively equating -- for him -- the equivalent of a "sun-dip" SM boost or an uber-enraged Hulk, or WW wearing the Gauntlets of Atlas, et al, meaning that his "normal" strength range is much less than that of SM's, WW's, etc. Not saying He-Man ain't the... well, "man"... in his world, but in the broader scale of things, he really isn't up with the real big boys/girls... Magic goes a long way in terms of boosting his greater feats.