In Buddhism there's no soul. That's another word that is not used in Buddhism because again soul means a permanent, unchanging essence that travels through bodies and continues on. Again we're talking about reincarnation if a person combines a soul with reincarnation theory.
The word 'mind' has two meanings. One of course is our own mind where the brain is and thinks and so on, another meaning in the Pali language is Citta - and the Thais point to the heart.
In English, Citta basically means heart/mind. There's no single English word for this one - it's kind of like the center of our "being".
I was going to say the center of our reaction, the center of our thinking. The mind in our head is just a brain that actually functions like our hand, but the Thais feel there's something else that comes before the brain.
Now as to the Citta mind, teachers even here in Thailand argue about what it means. Some teachers say Citta is something that is permanent. Other teachers say, "No, no, Citta is not permanent." So even within Thai Buddhism that has been here for over 2000 years there are teachers who are not in 100% agreement with what the word Citta means.
The other questions really aren't relevant - how close are they to each other, can they be separated from each other, since Buddhism has no soul as a definition then the question doesn't really apply.