Not all formalizations that give the same observed predictions have the same Kolmogorov complexity, and this is true even for much less rigorous notions of complexity.

Sure. But MWI and CI use the same formulae. They take the same inputs and produce the same outputs.

Everything else is just that -- interpretation.

One simple thing it could do is simply use trial division. But another could use some more complicated process, like say brute force searching for a generator of (Z/pZ)*.

And those would be different calculations.

In this case, the math being used is pretty similar,

No, it's the same math.