I think what you mean is 'counsel' which should certainly be accepted. However, 'council' has a different meaning in English (pertaining to a group of decision-makers usually).
'Thanks for the good council' is fine here. It's not as common, but should be accepted. Council would probably infer it was more serious advice, due to its informality. Reported :)
Then I'm pretty sure you'd use 'thank you' not 'thanks'. It is, as you said, a formal expression
"pelo" is the contraction of "por" and "o" - E: "for/by the". It is also in the portuguese.
It makes the thanks more specific.You are thanking them for that exact piece of advice, not the advice they have given you over multiple occasions.
"Bom" is that kind of adjective that is usually placed before nouns. "Bom conselho" and "conselho bom" mean the same thing.