Is there a notion of cultivating "sensitivity" in Epicureanism?

Most of that is beyond my experience to comment on, but it does call to mind this passage in the biography of Epicurus, which indicates to me that he would be interested in the direction you are studying. Hopefully others who are familiar with some of those therapies will have more helpful comment.

Some thoughts regarding the question: "Is there a notion of cultivating "sensitivity" in Epicureanism".

I would say that for myself, I am cultivating the ability to be aware and to reason regarding the nature of pleasure and pain in my body and mind. This would be based on several of the Principle Doctrines.

PD8 -"No pleasure is bad in itself; but the means of paying for some pleasures bring with them disturbances many times greater than the pleasures themselves."

PD29 -"Among desires, some are natural and necesary, some are natural and unnecessary, and some are unnatural and unnecessary (arising instead from groundless opinion).

Quote from Root304

I've mainly been intrigued with the ideas in Internal Family Systems therapy, where the mind is seen as having a multiplicity of personalities that we engage with in a social way in the therapeutic space (the inner critics, the inner children, ect). The angry inner voices are "entities" we should engage with.

I am not familar with this therapy, nor the others you mention.

You might like to look into the writings of Philodemus "On Anger". I haven't studied it, but Don has, and could point to threads or material to read.

Some further thoughts -- Modern therapy is very different than Epicureanism, and according to this Wikipedia article on psychotherapy, is thought to have begun in 1879. And now there are many new therapies, which may not be "evidence based". I hold a materialist and scientific understanding of the world, and so personally I would avoid any therapy which is not scientifically tested. Here is a website explaining evidence based therapy.

Quote from Root304

I got a lot of pleasure and a settled mind in doing the work,

That sounds great! So if you find it is helpful and leads to more enjoyment (and less pain) that sounds like it is good for you. We each find pleasure in many different ways. Others here on the forum have other avenues in which they seek pleasure. Life really presents a "smorgasbord" of pleasure, we just need to open up to it.

@Root304 , I'll admit I was unfamiliar with the topics you mentioned. At the risk of simplifying things, for myself and others, here are relevant Wikipedia articles:

Internal Family Systems Model - Wikipedia

Somatics - Wikipedia

en.wikipedia.org

Please feel free to tell me if these are off the mark!

My sense is that anything that truly and honestly makes us more aware of our bodies, our reactions to stimuli, and our feelings of pleasure and pain will make us more able to apply the faculty of choice and rejection. That's a good thing. I get the impression that we all try to lie to ourselves and try to make ourselves believe and/or behave in ways counter to our well-being (eudaimonia) all too often. That's what I believe one of the benefits of the practice of frank speech and correction in the ancient Epicurean community was. You may fool yourself, but you can't necessarily fool your friends or your teacher. You have to be open to correction and direction. Being able to do this yourself would be a boon.

I look forward to hearing more and hope this was helpful.

PS. This is also where the work of Dr. Lisa Feldman Barrett and others comes in, too. Cultivating our sense of interoception allows us to listen closer to our body's signals. I'd suggest checking out her books as well.