I think they could do some great accessories for Bing Bong's hat and tail! Like they did for the Haunted Mansion Portrait and the Cheshire Cat. They could also put an accessory on Fear's head and give Riley a backpack accessory. I would like to see Joy and Disgust on the Minnie mold too.
I also think it would be awesome to include Bing Bong disappearing as a variant, in the same way they made a Vinylmation of the Cheshire Cat disappearing:
Finally, for the chaser, I would choose Rainbow Unicorn:
Again, I think they could do some great things with an accessory for her horn, and maybe even her hair. I know Inside Out is not a recent release, and is now available to own on DVD and Blu-ray, but I still think this series would be a big hit! I know if it was made well, I would buy a case!