Whatever happened to your pdf, I can't find it. I think I have a good enough picture from your description, though.
A "change of fingers" is the same sign as a slur (14). But that is for two consecutive fingerings following one note. I agree with you that the minus sign is a visual cue and can be left out, especially since the author did not use it in the actual songs.
You are doing fine work, making very sensible decisions where they are needed!
Cheers to you!