Hi Cairyn thanks a lot for your time.
Yes there is some disorder between the geometry but as they are in a group with correct transform this doesnt make problems right? At least for rigid things moving like parents (IE: ARM2FrontRight ARM2RearRirght and FRONTALE)
I tried aligning joints with the align tool. My rule was to keep Y up aligned with mechanical Y vector, and have Z pointing to next joint. I am still confused about considering or not the last tilting thing on the FRONTAL. Because yes, they need to be in same planar space to correctly calculate... but this is a real thing, why is it so hard to make an IK and block only certain rotation axes to make it "mechanical"?