Glowing and Animated mobs

a) I don't know. b) If you use Blockbench, you can select "Skin" type when you start on a model, allowing you to change vanilla mobs to your desire but still keep the animations. To make an animated texture, that's a little trickier, but it doesn't require you to download anything.

How would I achieve the animated mob texture?

If you want to make a glowing texture, make a texture for the parts you wish to glow and input that texture into the overlay slot in the mob creator page

I didn't find the "skin" option in the blockbench, where is it ??