AFAIK the only Judy hybrids out there are V2/Judy and NEA(Posette)/Judy.

All use V2 mapping.

Yes, V4's tounge actors are a real pain, and not just for hybrids.
One of her main problems is that the Poser SetUp room can't handle her multilayered cr2.

I managed to create a "V4 head on actual V3 body to get bodymorphs" hybrid that "sorta" worked, but gave up because I didn't feel like spending days rummaging through that uber complicated cr2 hunting for line breaks or comma errors to fix the broken erc.

The only version of V4.2 I use ATM is the 17k LOD LoRez version that comes free with DAZ Studio and which I modified myself.
I copied V4.2's body and head-morphs into a regular cr2 to use her in Poser.
I also DELETED all that JSM Magnet and JCM morph nonsense and replaced them with proper morphbrush fix morphs.
This not only makes her bend like an actual human being, it also free's up A LOT of precious RAM that I'd rather use for adding other stuff to a Poser scene.

She's now even lighter than Posette and renders beautifully.

Hmm, back to Judy.....

Maybe instead of plucking the remapped HighRez V4 head onto Judy and then having to remap Judy's body to V3 specs, I'd suggest to use the V4.2 LowRez 17kLOD head on Judy and then remapping that LOD head to use V2 textures.

Should be a lot easier on the nerves and faster,too.

Besides, V3's UV's are "protected" by V3's EULA, while V2's mapping are free to use.