alphashitlord said:
I'm trying to tag Fallenshadow's alternate outfits, but I'm confused about post #6420026 and its children because everywhere I look seems to group them all together as her "second costume". Should I still try to give them separate tags just to be safe?
We have quite a few of these sorts of composite/combination costumes - examples include Lain Paterson (2nd Costume), Gundou Mirei (6th Costume), Ratna Petit (2nd Costume), and the closest thing to your case, Ange Katrina (5th Costume). The main thing that leads to them being lumped together, both officially and by fans, is them having some shared element that is present in all versions the costume can have; whether it be Lain's ribbed shirt, Gundou's black dress, Ratna's shoes, skirt and collar, or everything below Ange's waist.
Looking at your case, and looking at how places like the VTuber Wiki label stuff, the impression I'm getting is that post #6420026 is her 1st costume, while its children are all lumped together as the same costume (this is bolstered by the fact that the main dress elements of the child posts share the same underskirt and boot assets, while the socks are also retained for the undergarment), so by all accounts those should all count as her 2nd. Given the fact that she has the option to mix and match elements from each version of her 2nd costume, it's safer to lump them together to account for variation in fanart.