No, "good student" is not an idiomatic expression. It simply refers to a student who performs well academically.
Body is a word -- it can't be an idiom. You can find many meanings for this word in any good online dictionary.
This mean someone is pretending to have good intentions, but in fact, it's just the opposite.
The speaker is asking what you have been doing, with the expectation--or hope--that maybe you have been naughty. It is probably derivative of "having been up to no good," meaning doing something bad or not worthwhile.
Good hearted.you are a nice kind sweet warm person.
I think you mean "apple PIE order," which means in very good order or very well organized.
The idiomatic meaning of keep the pot boiling means to to keep it going actively.
It means 'I have not actually done it but I am going to do it so soon that you can go ahead and act as if I have done it'. A rather meaningless phrase.
"Keep up the work" really isn't a common idiom, so I don't have another idiom that means the same. Sometimes you hear "keep up the good work," which means to continue doing a good job, to keep on with the quality you're doing now. However, I still can't think of another idiomatic expression that means the same thing...
Yes, it's British equivalent.
The idiom "that's a good point" is used to acknowledge a valid or convincing argument made by someone, indicating agreement or approval of their perspective.
à la bonne heure is an idiomatic expression for satisfaction, like 'great!' in English. Literally it should mean 'at the good hour', which means nothing in French.