Judging by the look of the bottles and the semi-matching colors, I think they’re holding nail polish? They’re all also WEARING nail polish so maybe those are the colors they used. What makes me hesitate is that…it’s weird to pose like this just for nail polish, and the bottle AJ is holding has a big heart on it. I don’t know of any brands that have a heart logo. And I own a metric shit ton of nail polish.
 
That aside though, these are some cute cosplays, and pretty ladies. Not too sure why Rainbow is in a dress (but judging by the shoes it might be gala inspired? So that would explain that.) I love AJ’s boots and Pinkie’s heels though. Those are niiiice. Not a big fan of Rarity’s shoes but…I sort of hate that look anyways. But it’s an “in” fashion right now so…there’s that. I do like Rarity’s choice of fabric for her dress though, so that sort of balances out my hate of the shoes. And really nice wigs all around.

Who downvotes an image like this!?
 
Also, what are they holding? They look like D batteries, but I’m sure that’s not the case, funny thought though.