First, I will say that it’s awesome that you know what you would like to focus on… you’re half way!
Creature FX or TechAnim is at the cross of Animation, Rigging and Groom. They do usually dynamic simulations and shot finaling before to deliver to Lighting. Most of the studios out of there have a different approach and organisation about it.
Framestore has separated departments and uses proprietary tools: artists develop and use simRigs to play with Cloth, Skin, Fur, Feather and any extra props that are too difficult to animate. Muscle are animated by Animators but extra simulations can be added by CFX on top of it for a better realism. Of course, rigs make everything possible!
DNEG has a mixed Rigging and CFX department. You still have to focus on one field (Rigging or dynamic simulations), however artists have and need to have a general background, to be flexible to help depending on the production. Even there, you can focus on Muscle or whatever you’re keen to specialise…
Trixter, MPC have a different set-up too. Some artists are only doing shot finaling there…
Then about software. Most of the studios have their own pipeline and workflow… proprietary tools with a mix or not of Maya, Houdini, Marvelous, Qualoth, Ziva, Xgen, Yeti…
Whatever the software, it’s a tool and you can learn it. The most important thing is to have an overview and an good understanding of the workflow, what you need to do and why.
And as we do development as well, if you have a knowledge of scripting in Python… it’s a BIG plus for a recruiter, lead to hire you, as for your next team !
I hope it’s clear enough for you to understand this amazing world!