Allow me to ask 4 questions

Dear experts,
Please allow me to ask 5 following questions.

Question 1:
Sorry you can't do that. Rules are rules, you know.
In this sentence, "Rules are rules." okay? Or should it be "The rules are rules."?

Question 2:
Sorry, no drinking for you because you are still underage.
In this sentence, "you are still underage" okay? Or should it be "you are still underaged"? Or maybe better to say "you are still minor" instead?

Question 3:
Are these expressions equally common? Or some are strange English?
Does that mean you agree?
Does that mean you will agree?
Does that mean you would agree?
Does that mean you can agree?
Does that mean you could agree?

Question 4:
Which of the following makes more sense in general terms?
Are there any objections?
Are there any objection?

Thank you very much.