To me, it should be "seventeenth-century cultural norms". Hyphenation is ususally dropped with pretty common compounds, which does not seem to be the case in my humble opinion. Hope this helps!

Both imply possibility, but "might" is used when the probability is much lower. Hope this helps!

It's "in my email" or "in my message". Cheers!

Common nouns: house, man, woman, dog... Concrete: The White House, John, Alice, Laika... Hope this helps!

It is. In this case X-ray refers to the electromagnetic radiation.

It's not necessary. You say "The Smith Family" or "The Smiths". You use to show possession, not to refer the whole family: Mr. Smith's family lives in Texas. Hope this helps!

Other than stylistic, IMHO your sentences are good. You use "one" instead of "you", which is clearly British. What I would recomend is to try to avoid the repetition of "one" by means of changing the style somehow. For example, in "When one’s

"Investigate" means to inquire into (a situation or problem, especially a crime or death) thoroughly; to examine systematically, especially. in order to discover the truth. Having said this, I bet you can make your own sentence, can't you?

The subjunctive refers to a verb used in certain structures, not in what you wnat to express. If I were you, I wouln't do it. It's important that he be informed inmediately. These sentences are in subjuctive form. However, this is not so

"Lay" means "cause to lie" and needs a direct object, while "lie" means "to be situated, especially on a horizontal position". Compare: Please, lay this cover on the bed. Please take off the cover that lies on the bed. The "rule-of-thumb"