Maybe try looking at loli/flatchested illustrations for reference, A-F? :V
I want to see the full size picture, but i'm sitting in class and while it's TECHNICALLY SFW, people in the back of the class would be able to see those knockers if I put them on screen. So... later.
Also, Helepolis brings up a good question with his Purvis syringes: what kind of custom/boss specific danmaku/familiar are we going to want? To make things easy on the people making the sprites, I think we should keep from going overboard and keeping it to things that really fit well, but how about we open the floor for suggestions?
I'll start off with a few:
Slaves - Pencils or Crayons (maybe could even reuse Rou's pencils)
Purvis: HOBO NICKELS, syringes
Letty: Snowballs
Edible: Red Circle with Line (I.E "No ___" sign), i.e. :edibledoesnotapprove:
And we'll probably need to make some kind of 'e we' danmaku at some point.