I really like this concept. The entire backstory fits right in with the kind of stuff that happens in the Matoran Universe.
My favourite part of the model is the head. It really does like a Zyglak head despite using none of the same pieces (not in the same spots, at least). The creative use of the blades in the arm construction is awesome as well; I love seeing unique parts usage like that.
One thing I might change is the placement of the Toa’s hand. Putting it off-centre or at an angle (or just asymmetrically in general) would reinforce the chaotic nature of the Feglak’s creation.