Inc is short for increase, not ‘including’.
The increase to be used is usually shown in the pattern but if it’s not then it doesn’t matter which increase you use just as long as you are consistent and use the same increase(s) throughout.
Click on the tab above which is labelled ‘basic techniques’ and then ‘increases’ for examples of different methods.
I don’t unless it’s on the seaming edges, I personally don’t like the little bar it makes. I tend to use the M1F/B more often, it’s more invisible. But it’s really just a personal thing, you could use any you like :shrug: