Sorry about the lack of clarity, I just really didn't know which problem to bring up first.
When I finished UV mapping meshes, applying textures, etc., I exported the enitre model as a .nif, attempted to make the appropriate adjustments in NifSkope, and part way through noticed that the UV map data was missing, with all points mapped at (0,0). The new model was also lacking tangents and bitangents, which were present in the original model, and had a different number of vertices.
I tried to find a workaround by exporting each mesh on the model as a .3DS and importing them into a separate instance of NifSkope. UV map data was present, but when I tried to copy the NiTriShapes for the meshes into the instance containing the un-UV mapped model, the UV map was skewed in the process.
Trying to import the meshes as .obj had the same result, though I think something bad would've happened regardless.
I made sure to uncheck the body parts option on export and try most of these things again before posting. No luck: the UV map data staunchly refuses to cooperate in NifSkope.
Thanks for the quick response; if there's still more tips to give, I'd be glad to hear them. At any rate, I think the problem might be related to what I've tried to do with the model in Blender. I'm gonna continue to fiddle around with it, perhaps scale back the changes I made. Wish me luck, and thanks again!