Don't know if it can be done. 3d printing while no longer in it's infancy is definitely still in the late toddler stage, though that opinion would be up for debate. Anyway I managed to get my Ender 3 Pro back up and running with new parts. This was something I wanted to try.
Here is try number one. I've torn the poor girl's lips at the corners trying to apply makeup (massive failure) so that's going add another dimension of difficulty to this project.
Here is the as is:

Yeah, I had problems with the eyelashes, too. Makeup is definitely not my thing. She's wide-eyed and confused looking. That's been my personal issue with the SDH-C22 head from the time I first saw it.
Anna was still the best choice for me, but let's try to improve that "deer in the headlights" look.

This is try #1. Not successful by a longshot, but a beginning. I've got the lips parted a bit, but the tears at the corners happen to go downward. That's going to make creating a smile a little more difficult.
Now she just looks really surprised. That'll be useful when the new buttplug comes in from China at the end of April! 😁
This is the design of the mouth insert.

This is the actual piece.

It's really difficult to 3d print something that small. 30.58mm long. 3.37mm wide and 4mm tall. The downside is it obviously didn't achieve the smile I was going for. The upside is, I think I can go much more robust with the measurements.
Without getting too technical, to get it that small I had to go with a material that is very strong, but ugly and difficult to work with. Being able to increase the size of the piece will allow me to print with a different material with more color choices and it won't be such a PIA to print.
Currently designing try number 2. I'll keep ya'll informed, because what the heck? As far as I know, no one has tried this before.
@NinjaGirl Okay! Those are even better! They really do look Natural.... Great Job! As for her Faraway Look....it really will soften and change, when you give her some Top and Bottom Eyelashes... Just apply the same focus you have on her Teeth, to learning to glue those Eyelashes on, neatly. You can do it. Then, a little Eyeshadow....Fresh Lip Gloss...and...Her Totally Magical Babeliciousness, will really shine out!
Thank you all for your comments. I took it a few steps further, and I am now happy with the results (for the time being). I present to you Aredhel's Smile:
She's still got that faraway look, but considering her backstory it's understandable. Personally, I would like to do away with the black eyeliner, but since it's in the superglue, she's pretty stuck with it for the time being.
I took Kevin's advice and made the teeth shorter. This is iteration number 28. Teeth? What teeth? you can barely see them, right? Yep, and thank you.
She just gets hotter and hotter. More to come.
@NinjaGirl Wow! Just, Wow! I honestly think you’ve nailed it! Seriously...if you don’t like that set....Send them to me! I will put them in my Girl! They look great!
Much better! It was the camera angle then. The first shot was looking up at her and that made them appear longer. The other shots are more level and make the teeth look better. Awesome job on this! I get obsessed on projects too, that OCD of mine... (I think if you take shots of her from below just tilt the head down to face the camera and they will still turn out awesome!)
I think they are awesome! (Maybe a little long though? Need some more pics.)
I've been looking at, and designing teeth for what seems like a very long time, now. I believe this is my 24th version. I've lost track, I've got so many different tries and versions in so many different folders.
Anyway, I think I've got it. What do ya'll think? Please be honest. Height, width, shape, position in the mouth, anything... really, be honest.
I've sort of thrown my heart into this little project, and I think the print looks like teeth, and gives her a hint of a smile. I've gotten too close to the project, though. Perhaps a little obsessed. I can no longer see the woods for the trees.
I'm not grubbing for affirmation. I really do want honest opinions. Thank you.
@Fantastic Plastic (Or anyone else who has an idea.) The SDH-C22 head has what could be painted as upper teeth:
There below her upper lip. I want to remove it. Is there a way to cut, dissolve, melt or otherwise safely remove that piece of TPE?
OK. next version. What do ya'll think?
Well you are sure going to have a market when these are done, I'd buy one!
Well, we've the hint of a smile, and I think she looks darn good.
Definitely getting closer. Still a ways to go.
OK. Trying to 3d print a smile is going to open her mouth. I can work with that. Here's the first attempt at smile-inducing lower teeth.
I need to add some "bumps" at the top, to replicate teeth. MUCH easier said than done.
I can't create the upper teeth, because she already has those molded in. I might could ignore that and work around it.
It was just going to be a "U" shaped insert to lift up the corner of her lips into a smile. It has become much more complicated than that.
At this point, I've got a lot of thinking to do. More to follow.
Much better!