no, not a separate genital figure. sorry, i was being unclear.  2 different full characters.  the community went away from different characters because DAZ didn't allow it.  V1 and V2 were the same mesh, but V2 had more morphs.  so they didn't want people distributing V2 characters and giving V1 owners an incidental upgrade.  this continues to be an issue with just about any commercial morph set.  it was driven by commercial needs, not by usability.  i mean, there are benefits, but there are a lot of drawbacks as well.  and you're the creator.  DAZ provides multiple characters, and it's not a problem.  you're in their role, not the average developer's.

in this case, i'm not sure i see a huge benefit compared to needing to bog down the main runtime even more and use something that will almost certainly break for a significant percentage of the audience because complicated technology does that.

though, i will say as someone who likes extreme poses, i'm kind of skeptical that avoiding a conforming genital will solve the problems you're describing. they don't need to bend with the figure, they need to move based on the pose and orientation.  which means, in my experience with female figures and hair and breasts, for most of those situations, mostly separately.  a split on the ground produces entirely different behavior than a vertical split.  laying flat on the back on the ground is complete different than standing straight up or even laying flat on the stomach.  it's actually the "we know how this should behave" items that need specific poses, because when you go outside of the expected you have unwanted effects. 

and i know this because i always find myself outside of the expected poses, fighting what the creator thought would work.  i don't know what it is about me, but even when i think i've chosen a pose that should work with something, i'm wrong.  9 times out of 10, even conforming rather than parenting is inconvenient because of this.   i have NBM for V3, and found auto-mode just about never worked out for me.

i say this just as an FYI, not because i want to talk you out of anything.  i've never found they rendered off, or had the problems that others have with that, so i certainly know nothing about (and have nothing against) solving it.  but in terms of performance with poses, i suspect that the difference is just you created one and you didn't create the others.  if you made your own conforming figure, it would probably work well in your tests, too.  that doesn't mean it will work well for anyone else who thinks differently and can't sculpt their own morphs.  so don't be disappointed if people have the same problems you just described, but more so because it does change automatically instead of exactly as the user decides.