Hyphens, En Dashes, Em Dashes

Q. Should “cotton gin maker” have a hyphen? Does “cotton gin” here serve as an adjective, necessitating the hyphen? I’ve consulted CMOS and am still not quite sure. Thanks!

Q. I’ve been looking for a format on writing date ranges but cannot find any. How do I write a range without a death year or without a birth year? Should it be First I. Last (1804–?) or First I. Last (b. 1804)? Or is there any other way? What if you are unsure of the year because sources say different things?

Q. Do open compounds like “face mask,” “cell phone,” “sea level,” “high school,” and “life science” (all identified as nouns by Merriam-Webster) have to be hyphenated before a noun?

Q. Hi! Is it ever appropriate to follow an em dash with a period if it’s the terminus of the sentence? Thanks!

Q. How would you handle “early-to-mid” + “century”? “Early to mid-twentieth century”? “Early-to-mid twentieth century”? “Early-to-mid-twentieth century”?

Q. Working on an architecture book that uses a lot of duplex addresses—i.e., 1522-1524 Main Street. Thought it should be an en, but someone pointed out the numbers are not inclusive, as 1523 Main Street is not part of the address. Is that correct? Should it just be a hyphen? Thanks!

Q. Would it be correct to use an en dash instead of a hyphen in a compound like “singer-songwriter”? What about a slash?

Q. Hi! Would “results sharing” be hyphenated in this example? “Each webcast includes in-session polling and results sharing.” Thanks!

Q. Hello! I understand that hyphens work like “treatment-naive patients” but “patients are treatment naive.” However, what would you recommend if the modifier is used alone—e.g., in a graph key? Hyphen or open? Should the key be “Treatment-naive” and “Previously treated,” or “Treatment naive” and “Previously treated”? Thank you!

Q. Hi. I’m working on a label for an image in a printed brochure. The entire label is “bison shoulder blade hoe.” How would you punctuate that—with an en dash (“bison–shoulder blade hoe”)? Or hyphens (“bison-shoulder-blade hoe” or “bison shoulder-blade hoe”)? I was thinking that technically an en dash would be correct according to CMOS 6.80, but that seems too formal and, as CMOS states, unlikely to be noticed by most. There is no room to reword it. Thank you!

Q. Regarding open compounds, would an en dash be correct in “Mr. Potato Head–like head” and “rubbing alcohol–soaked cotton”? Thank you!