You are going to have to rebuild the add on's joint work (digigrade legs right?)

also GND4 is still V4 so you inject the CC morphs like any V4

A word is not the same with one writer as with another. One tears it from his guts. The other pulls it out of his overcoat pocket
Charles Péguy

 Heat and animosity, contest and conflict, may sharpen the wits, although they rarely do;they never strengthen the understanding, clear the perspicacity, guide the judgment, or improve the heart
Walter Savage Landor

So is that TTFN or TANSTAAFL?