I bought that Johann Schmidt Red Skull head cast and Hydra hat from Casting Cave, a while ago. I haven't seen the hat on Casting Cave, anymore, but the head cast is currently available. I'm pretty sure they're both shrunken down casts of the Hot Toys figure.
That Tesseract was also a custom cast, that is UV interactive. Those pictures were taken, using a hand-held black light, to accomplish that blue glow.