>>53423193My thought is something like this. Iron Hands gets inverted, with the thighs functioning as the shoulders, with the head and legs being tucked in. Iron Thorns is below that, with the neck holes interlocking.
Miraidon and Iron Leaves form the legs with the head folding upward into a foot in each case.
Iron Moth anchors into Iron Hands to be the head, and Valiant reshapes with its blades to be the sword.
Iron Bundle and Iron Jugulis could potentially go in a lot of spots, since they've got cannons to shoot water and lasers. Best place might be the shoulders to give another anchor point for the arms when they're not being levitated outward.
Iron Treads I think would be best on the back, either positioned akin to a spare tire, or with the trunk being extended as far as possible to resemble a spine.
Honestly I'm least satisfied with the legs, though I think the only other option would be for Iron Thorns to split itself down the middle to form each one, while Iron Leaves combines with Iron Valiant into an even bigger sword, with Miraidon potentially being split into the front and back and connected to the shoulders to serve as a pair of physical arms for the otherwise floating hands.