Yes. It would be nice of them to do that but not every coworker will.
her father bought her the diary for her 12th birthday.
Bought , party
Yes, you should call and thank the person for your birthday gift as it shows you appreciate the effort they made for you.
yes!
Yes, you should still give the child his gift.
Yes. Anytime you use a title (like "mom") in place of a name, it should be capitalized. I gave Mom a gift. (Instead of: I gave Sue a gift.) I gave my mom a gift. I asked Mother a question. (Instead of: I asked Susan a question.) I asked my mother a question.
Yes i will do it
Yes. There is no reason why only one person should be able to give a gift.
the man who sent the present?
Depends on who's birthday it is... if its a good friend or family definitely give a gift. Giving flowers to a friend is fine to.
A gift certificate to his or her favorite restaurant or bookstore.
A gift card to walmart