What will we have for dinner? OR What will we be having for dinner? Please can anyone advise me the correct sentence?

All are correct:

What will we have for dinner?
What will we be having for dinner?
What are we having for dinner?
What are we going to have for dinner?
What shall we have for dinner?

The last questions changes the direction of the question, inviting someone else to participate in the choice.

Thank you for your reply. Always good to get some feedback.