What Exactly Happens When Models Merge Together?

I never personally printed anything before and would like to know more about what exactly happens when a model fuses together due to insufficient clearance. I'm planning to print a small 50mm model and the mouth, which you can see above, is 20mm across. On bottom is the original, and on top is a version with Merge by Distance applied in Blender to vertices less than 0.9mm apart - so as to emulate what I'm expecting to happen once the model is printed in full color sandstone, since 0.9mm is the clearance indicated on the documentation.

If the result turns out as the model on top, I believe the print will turn out acceptable, even with some merging, since it still retains most of the relief detail for a clear visual as to what is being represented on the surface of the 50mm model. If not, I will have to reduce polycount and make the model more stylized, I suppose.

By the way, is the only consequence of Zero Faces and Zero Edges that the print fuses and lessens in resolution, or will they also cause the print to fail completely?

Pardon, I think the post wasn't clear enough. The 50mm model I'm making includes a single non-moving mouth, and the whole model itself doesn't have moving parts either. The two mouths you see above are just for comparison between each other, they won't be printed together. The question of the post is if the mouth on top is an accurate representation of what to expect due to insufficient clearance between the vertices, in this case less than the recommended 0.9mm for sandstone.

Alright, that cleared some doubts, thanks.