I'm sill in the learning process for chords progressions, so I'm sorry in advance if my questions are simplistic for some advanced musicians.
I've watched several harmonic analysis (Youtube, websites...) of classical music (Moonlight sonata, mozart...) and it would appear to me (correct me if I'm wrong), that progressions can switch from one mode to another, starts on triads and then introduce augmented 7th, or else...I'm not talking about modulations here.
Am I right to assume that mode (ionian, dorian...), scale, chord type (triads, augmented...) and of course modulating key can always change in a progression? And of course on the top of that you have all possible inversions.
Also, I've noticed that sometimes you have 2 chords for a bar, one for the left hand and for the right hand? So we can combine or superimposed chords when they share enough common notes? Is that correct?
Any help on this would be appreciated.