I don’t feel confident in answering the others, but what I have done for question 5 is as follows:

WASD is standard movement for the main.
` is the follow key for all followers.
Up arrow has been rebound depending on the character. E.g. it does nothing for the main. Tells alt 1 to go left, alt 2 to go right, and alt 3 to go forward. Down arrow does the opposite.

So generally they follow, then in preparation for a fight, I press and hold up arrow for a second to get into formation. Kill whatever, then press ` again to recommence following.