It's an interesting suggestion.

The way I'm thinking about this right now is that the app would automatically set the transform properties when the character is referenced in the mouth point/coupling.

Mouth point feels a bit more straightforward. Coupling is a bit more complicated though, considering there probably isn't a direct way to make an already posed character appear in the same way once coupled, or if it is, it probably wouldn't work properly as the character would have to be offset in order to appear at the same location prior to referencing. So coupling would most likely always "snap" the character a bit. Although, this snapping could be made less jarring, so it sort of tries to retain the location, but will still cause the snapping to occur so to speak.

So I could create a keyframe, set the mouthpoint to none, let the head move to where it needs to be for the transform and lookat node, then set the mouthpoint to the character again to snap the mouthpoint to the head's current position and rotation? That works for me. Basically I want the character to pull out of a kiss and look at a target seamlessly and vice-versa.

For the coupling that's definitely more tricky. I am finding that if I set the leaning to none, I can get everything to be seamless between coupled and uncoupled EXCEPT for the cock, which jumps a bit when it "attaches". It's a pretty minor cosmetic issue, could maybe add a "PenisTipIK" node way down the line heh.

Addendum for New Version: Actually the fix to "Influence" mostly solves this problem, I can just tween the influence down from 1 to 0 and then disconnect the mouth point. And then do the reverse when I want to control the mouth again.

Thanks! Great Job!