Infernum Advise and Ideas

So I'm cracking open my Infernum books to prepare for a game to run, and I want some advise on designing some new Mutations. I'll also be happy to share some new material of my own (new First Tribes, Minor House details, etc; setting alterations) as I flesh it out.

Fist off, how would you handle a mutation to give a demon (or Corruption-infected mortal or angel) multiple mouths on their body? I don't believe Devourer handles this.

What about a serpentine form? My best idea right now is to make it a branch off the Carriage, as the demon's tail becomes their entire lower extremity.
*really hoping there are still people who play or worked on Infernum around*

I noticed something odd... Their description casts the Beasts as Hell's primary Sorcerers, but nothing seems to particularly mechanically facilitate that. All the other breeds have their "nitch"/"purpose" emphasized in their Mutation Chain.

Another side note, anyone have any idea as to whatHouse Jelac's unique themes were?