Those are a lot of questions.
I will answer just two of them:
1) The ch and sh do not behave the same in the VMS. This is based on my own research.
Could the cap on sh be an abbreviation symbol?
2) In Latin this is usually an abbreviation symbol, quite a common one. But is it an abbreviation symbol in the VMS? I don't know.
In the VMS, it is sometimes written like a curved macron and sometimes like a superscripted Latin 9 abbreviation (-us/-um) but this might not have anything to do with its meaning, it might only mean that the scribes were accustomed to writing in Latin and sometimes reverted to familiar movements of the hand, so the distinction has to be studied on a statistical level for now.
I will answer just two of them:
1) The ch and sh do not behave the same in the VMS. This is based on my own research.
Could the cap on sh be an abbreviation symbol?
2) In Latin this is usually an abbreviation symbol, quite a common one. But is it an abbreviation symbol in the VMS? I don't know.
In the VMS, it is sometimes written like a curved macron and sometimes like a superscripted Latin 9 abbreviation (-us/-um) but this might not have anything to do with its meaning, it might only mean that the scribes were accustomed to writing in Latin and sometimes reverted to familiar movements of the hand, so the distinction has to be studied on a statistical level for now.