italic\capital letters etc. Please help!

Hello,
Help is needed regarding the use of italic, Capital Letters or 'Capital Letters' when referring to terms or concepts.
For example –
1. Oedipus Complex, Oedipus Complex or 'Oedipus Complex' or Oedipus complex etc
2. How should the terms should be written ('Critical-Idealism' , 'materialistic-skeptical' )?
"I will show that although Freudenthal's 'Critical-Idealism' and Jung's 'materialistic-skeptical'."
3. Music, Philosophy… or Music, Philosophy? "This intellectual function is at the heart of every human capability, for good and evil - music, philosophy, art, war, envy, greed, poetry and murder"
4. 'intermediate betwixt' , intermediate betwixt or Intermediate Betwixt ?
"Hume defined this imperfect concept as 'intermediate betwixt'".

Many Thanks!