"ever" means "at any time" Interesting here is that you can replace "ever" with its opposite, "never", and the meaning stays the same! In both cases it is a complaint that it is taking too long to make dinner.

Basically, it is a request to hurry up with dinner.

They are asking if they are going to have dinner at some point in the future. It is a way to show their displeasure at how long it is taking before they eat dinner. Essentially it is saying, "Can we eat dinner already!" Ex: I have been studying English for years. Will I ever be fluent? >The person is upset and demoralized because it is taking a long time. They wonder if it will "ever" happen or happen at some point in the future at all.

are we ever having dinner? = are we never going to have dinner? as if the fight is taking forever and it doesn't seem to have an end, therefore, they are never gonna have the dinner.