I have the DLC, and it loads fine, but not without an error:
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Then the second error - whenever I try to load the save again, this happens:
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It seems like everything you get through the Teahouse is tied to system data (like character transformations), so maybe that error happens because my system data isn't matching up with the character data properly.
Edit - okay, nevermind, the second error is gone now. Must have been because I was still on system software 4.70, and I just updated to 4.71. Huge thanks for the save.