Translation:Sir, what plans do you have for next month?
Proximo mes is like saying next month, el mes que viene is saying the month that comes. So coming month would fit more accurately as a translation for el mes que viene but proximo mes imo is more accurately translated to next month.
Both should be accepted though. It's really all the same.
Hmm, that might have been some play on words (which doesn't translate well to English), but I don't think it'd be the difference between "next week" and "the following week".
Thinking about this, that example might translate as "Are you coming next week?" - "No, I'm coming the next week (after that)." Using "la semana próxima" can work in this specific context (next week vs. next-next week), but more as a play of words than any helpful information. It doesn't mean "the following week" in general.
You have the plans. :)
A construction like this where it's not entirely clear what the subject and what the object is is a common feature of Germanic languages. English normally uses the "do" auxiliary to solve it, but you don't use it with "to be" (where the difference between subject and object usually doesn't matter), and some dialects also don't use it with "to have". What have you?
The other Germanic languages don't have the "do" auxiliary, so sometimes you'll have such ambiguities. You seem to be learning German, so at some point you'll stumble upon things like "Was berührte die Frau?" ("What did the woman touch?" or "What touched the woman?") or "Würste essen die Kinder" (looks like "Sausages are eating the children" but is probably to mean "The children are eating sausages").
Por, when used with times, refers to the entire duration of that timeframe. For example: "Allí nos quedaremos por dos semanas" - "We will stay there for (the duration of) two weeks."
Para, on the other hand, is used for specific goals or deadlines. Here we're asking for plans within a certain timeframe in the future, so the goal-oriented para is used.
It's a literal translation and it doesn't sound correct in English.
Most Spanish to English translations involve some word flipping.
No, because when you addressing someone by sir, you use the polite él/ella/usted form. So it would be (él) tiene.
Don, the progress quiz measures your progress in comparison to the entire course. If you haven't completed the course yet, of course there will be things that you haven't encountered yet. The progress quiz is basically asking the question "How much can this course still teach you?"