1. If I was in your house and you said, "Would you like something to eat?", I would say, "What have you got?", not "What have you got to eat." It has been established twice that they are talking about eating, but I suppose it's a beginner's exercise.
No, "What do you have?" or "What have you got?" are more appropriate than "What would you like?". Besides these would have to be spoken by different people.
If it's Kevin's home, he might say,"What would you like?". Mark would not say this. Similarly, Mark would say "What have you got?" (in Kevin's house). Kevin would not say this. So you are suggesting a change in dialog that can't happen.
2.No. 'It' means all the food. 'Food' is uncountable here.
Student or Learner