- From my experience, seeing what other composers do, by analyzing their songs will help you with your music. I mean you can write a book, but if you read another book, you'll see what other authors are doing
- Dmin/C and Dmin7/C are pretty much the same. Technically, yes you have to mention the 7, but since the 7th is C and it's on the bass, it's shown on Dmin/C. D7/C and D/C are the same, like above. To be honest, since the analyst didn't include the 7th in the first example, it's inconsistent to do it here. The Major 7th chord can be symbolized both M7 and maj7.
You know what diminished a chord is, when you see what chord goes to the diminished one and where it leads to.
I don't think they used sus4 chords in Baroque music. Maybe it's delayed resolution. Ιf you notice, the C that is the 'sus4', is being played by the same voice on the previous beat and in the next it goes to B. That is the real note of the chord. Not sus4; that's wrong.
Yes, Ab dim is a correct chord.
The third from the end chord is F chord with the C on the bass. The notation is correct. The second from the end is G7, with the C as the bass. C isn't in the chord notes, but the composer is keeping it anyways. ( I don't remember the name in english exactly, will look it up). Τhis was pretty common in Bach's compositions.
- The way they are notated there is fine. Another thing you can do is that you can use roman numerals instead of the chord names. Like I, II7, V6-5 etc