You can usually track it by each brand’s history.
- AP flirts with just about every other trending substyle. They did it with gyaru, fairy kei, and are doing it recently with larme and menhera.
- AatP covers lolita, boystyle and ouji — and for a while in 2008? 2011? they tended to have whatever release didn’t strictly fit in with btssb, such as that jsk with a really short skirt, and then shorts jumpers at some point.
So pretty much anything from either of these brands stands a pretty strong argument for being a non lolita item produced by a brand that normally produces lolita clothing.
On the other hand
- Btssb tends to push their less lolita releases onto AatP, so up until 2013 at least, anything btssb releases I’d take it as fully intended to be pure lolita.
- And whilst you’re thinking VM also has Beth and MmM differentiates between EGA and EGL, that’s not what I would argue. I would actually argue that I put both of these (sub)brands into pure lolita because they show very little outside influences. Unlike the AP collage in lolita general, you could practically re-release an older VM or MmM dress from 2002 and it’d fit in with their modern lineup. I don’t think Moitie has even changed their basic silhoutte much. So whatever they’re doing, it’s almost a non-issue, because they’ve been doing it since nearly the dawn of lolita.
Conversely, brands like Lapin Agill, Millefleur, because they are the lolita sub brand of a gothic brand, I’m inclined to see that they can be argued to have very strong gothic influence rather than lolita, as their roots lie in gothic first and lolita after.
Just my two cents on which brands are “canon” lolita anyway.