Ekimu is implied to magically transform, I think. He doesn't really build himself new armour so he didn't exactly decide on his new appearence. The Lego Shop description for Ekimu the Mask Maker says Ekimu that is recovering his ancient strength, which is a plot point that is never really discussed in JtO.
So, really, all these details about G2 were so unclear that you're not contradicting canon if you give him crystal add-ons. I'd even say he looks good with them.