To put it short its just a concept to put together a team of kids who are from the world of the damned.
Characters are (starting from the left)
I think Lenore and that plushie are from Beetlejuice, but I am not sure I never watched that show...
Negral Jr. There was this monster guy Negral from Billy&Mandy who lives in the center of the earth and he is alone so once he kidnaps Billy&Mandy to play with him forever, he wears suit and has this elvis like hair and blue skin and he can generate tentacles from his back and zap the ones he holds in them. Obviously Negral Jr is the kid of that guy.
Grimm Jr and Mini-Mand ywas created by deaddoll00 at Deviantart.
Here is the link http://www.deviantart.com/view/12560418/
Her concept was that Mandy and Grim might fell in love and get married in the future and these 2 are their kids. However Mini Mandy somehow died and her body was rebuild from stuff not mentioned and her soul sealed in it.