Punctuation

Q. This may be impossible to answer, but I feel it’s important, so I’m gonna give it my best shot. This is how I would punctuate the following:

Can you believe that I said, “When she says, ‘Do you know which fruit Jim likes best: apples, bananas, or oranges?,’ tell her this: ‘Actually, I once overheard Jim say, “I only eat pears!” ’.”?!

Q. Hi, CMOS people. You answered a question for me a few days ago, about using a comma or a colon to introduce dialogue in a book project we are doing. We took your advice and are using commas. My friend, though, would still like to use a colon to introduce internal dialogue. (Michael thought: if I go home now, Mother will know I forgot something). Would that be OK, or should we stick to commas for everything? Thanks!!

Q. How should the sentence “Guess what” be punctuated? I realize that it’s technically an imperative sentence, which should end with a period (or exclamation point), but in many contexts it’s used as if it were interrogatory, and thus it’s often punctuated with a question mark rather than a period. Is this simply incorrect?

Q. Please tell me if it’s permissible to use a comma rather than a semicolon in the following sentence: “The idea isn’t to use the test to get people in trouble, it’s to help them avoid decisions they’ll regret later.” The rules seem to suggest that a semicolon is preferred but not absolutely required; a semicolon feels to me like it separates the thoughts more than I’d like.

Q. Is it “Hello Mr. Doe” or “Hello, Mr. Doe”?

Q. Is it necessary to use a comma after words like next, then, after that, last, and finally when they are the beginning of a sentence? I am a lower-school teacher and need to clarify this.