I think you should add a clothing DLC for the party "guests". You could probably charge $1-2/character for a full outfit. That could either fund better skins for the current version or put it towards the next version. I see some real potential.
I would totally buy new clothes for Ashley, Amy, and Rachel.
They are working on a "New Content Pack"
Description:
Want More House Party Content?
This DLC will include new clothing and hairstyle customization options for the House Party characters. (Some free hairstyle options will be coming to the customizer free before this content pack is released.)
With increased clothing and hairstyle options, and the options that are already built into the customizer, you'll be able to transform the House Party characters appearances even more than you can already! We’ll be announcing an official DLC title and more info on its content soon, so wishlist it today!