I also got a feeling like Virtue/Nadhleeh when I saw the Gushion and its small hand. I think some guys that were involved with Gundam 00 are involved with IBO. So this wouldn't be surprising if true.
It kinda looks like the concept sketches of the G-self. It certainly wouldn't be the first time concept sketches are re-purposed.
Whoever made this should get shot
I won't expect that they will do the same baffle like Virtue/Nadleeh from Gundam 00. It just won't be fascinating anymore if they KEEP REPEATING THE SAME SURPRISE !!!
So yeah it might have some cast off thing, but the mech would not look like that, it's too g-reco looking, since it is a gundam frame it would probs look closer to barbatos, at least in terms of having exposed inner frame and skinny abs
One of the silhouettes (MS C I think it was, the one similar to the Barbatos frame) might actually be the inside of the Gusion. Just a wild guess inspired by this post