Oddly enough Half-Scrag does not provide water breath, only swim speed. Still thats better than nothing I suppose. Although at this point, I calculate the beasties have a 20+ Str modifier, so they can succeed on swim checks in stormy water (DC=20) even on a 1.
However, to incorporate Half-Scrag into the already complicated breeding process was somewhat difficult. I have tried my best but I'm not sure if it works as described (you can read through the breeding process and let me know).
I've also replaced Stained Glass graft with Clay, to protect against Trollbane Alchemical Goo.
Also, Half-Ogre at +0 CR has this interesting little ability:
I wonder if "special abilities and effects" includes the Hlaf-Golem graft. If so, I can replace Half-Scrag with Half-Ogre and knock 2 points of the CR.Giant Blood (Ex): For all special abilities and effects, a half ogre is considered a giant in addition to the base creature's type and subtype. Half-ogres can use magic items with racially specific powers as giants.
Good point on the silence. I realize that it would protect against Holy Word as well. That said, with items of silence, the main threat isn't Area Dispel (which only targets spells not items), the main threat is disjunction which simply wipes out all magic in the area.
They are still voidminds, and would hence remain slaves to the cabal, even if they become constructs. Its mainly not having regen thats the problem.
And I'm still looking for ways to protect against supernatural Graymantle. Anyone have any ideas?