Using those alien biomos as inspiration for the novels is a great idea. Thanks for sharing your explorations with us. Also, good luck with the writing; hope it's going well.

I think vanilla Minecraft has added armadillos and a few more breeds of wolf, as well as wolf armor and the Crafter for automating crafting recipes. I don't know whether Mojang also added penguins oo not. And they also added those trial chambers you highlighted in one of your snapshot episodes. Source for the info: The Minecraft Survival Guide; channel Pixelriffs.