Slitherine

When stepping forward into a new enemy does each file have to make contact?
e.g. If the file next to a file which makes contact does not make contact but the next one along makes contact with a fresh enemy, which is within 2 Mus and still maintains a link with the a friendly file, is this legitimate?

Yes that is legitimate. You might have several files that can't step forward and only one that does, depending on the situation.