Can you, or should you? You can hyphenate it if you're moving between lines in a paragraph and need to break up the word. You shouldn't hyphenate it normally.
McCarthy should not be hyphenated.
not required
A hyphen is not required.
Yes it should be hyphenated.
Yes it should be hyphenated: co-worker.
Yes it should be hyphenated.
Yes, hyphenate by-laws.
According to the sources I've found on a quick search, you should hyphenate 'coauthor', i.e., it would better be: "co-author".
You do not need to hyphenate.
You do not hyphenate the number.
Don't hyphenate; ongoing is one word.