Student or Learner
What will/would you have in/for dinner?
What shall i make for/in dinner?
What would/will you like to have for dinner?
What you had for/in snacks?
What you had for/in breakfast?
4 - I'm not sure what you mean. Are you asking what the person had available to eat as a snack, or are you asking them what they ate as a snack?
Either way, "What did you have for snacks?" would work.
5 - What did you have for breakfast?
Remember that "had" when used in the interrogative becomes "did I/you/he/we/you/they have". You need the auxiliary "did".
also if i have to ask what is made for lunch what shall i say what is made for lunch is this correct or can this be better
Either of these are okay:
What did you have for breakfast/lunch?
What did you eat for breakfast/lunch?
What did you make for lunch?
What's for lunch?
I'm not a teacher, but I write for a living. Please don't ask me about 2nd conditionals, but I'm a safe bet for what reads well in (American) English.