As for your first question, I would consult my favorite style manual. Chicago Manual of Style Online has some examples about what you're referring to. The very first example on their Q&A page about the topic is relevant:
Q. When is it appropriate to use quotation marks to set off a term that is being defined or described in academic writing? I edit casebooks and journal articles for law professors, and authors will often write sentences such as:
It will be helpful first to explore the meaning of the concepts of “public health” and the “common good.”
I find quotation marks unnecessary unless they are used to set off words coined by the author or if their usage is not standard. What do you think?
A. I agree that the quotation marks aren’t needed in the sentence you cite, but the difference between that sentence and one like the following, where the quotation marks would be standard, is subtle:
It will be helpful first to explore the meaning of the phrases “public health” and the “common good.”
Although those phrases aren’t coined by the author or used in a nonstandard way, it’s conventional to quote or use italics for words or phrases being introduced or defined (CMOS 7.58). For that reason, I wouldn’t fuss if an author wanted to keep the quotation marks in sentences like the one you quote.
Different style manuals may have different ideas.
For the second question, it is a standard rule to put quotation marks around direct quotes, then cite your source according to what type of writing you are doing. See Grammarbook or other references.