I think that is totally fine. You can use both. Meal is something you use more general. Lunch and breakfast are meals, but a soup is a dish. I think you should use meal in singular, even if you are in company and you all together ate several dishes, that would be still one meal (lunch for example) for you all. You say 'the meal was delicious' and 'the dishes were delicious'. I am not great in English, I hope some native speaker will come up and confirm this

Yes, you can say the dishes were delicious. But you should say "The meal was delicious" even if you are talking about a group of friends eating together. this is because it is a (one) meal together.