I have fostered roughly 25 cats (one at a time), and what you wrote about communication resonates with me. Most cats seem to develop a sort of pidgin[1] language in collaboration with you to communicate how they feel or what they want. It's different for each cat, but is usually some combination of vocalization tones, body postures/movements, eye contact, or even the location in the house they choose to do those things from.
They can be surprisingly great communicators.