Verb to have + classes (expressing actions)

Use of the verb to have (Present Simple) - expressing actions
e.g. have classes
have lunch
have a bath

In all these cases I though that "have" had the forms of an ordinary verb.
Questions and negatives should be made with do or did. Am I wrong?

According to this, are the following sentences correct?

e.g. He hasn't lunch at home. or He doesn't have lunch at home.

e.g. No, they haven´t. They haven't classes on Saturday. or No, they don't. They don't have classes on Saturday.

e.g. Yes they have. (They have breakfast at 8 o'clock.) - short answer

or
Yes they do. They have breakfast at 8 o'clock. - short answer

Thanks in advance for your help