It doesn't make much of a sense, it depends on what you want to say. "in the table" is wrong, you should use "on" instead of "in" when an object is physically over something else and touches the surface, it kinda looks like a question but the sentence itself is not right, it could be intended as: What is(or what will be) on the table when the breakfast is ready? Is this(or will it be) a cup of tea?

in -> on, and a comma might make this sentence a bit clearer: What is on the table when breakfast is ready, is this cup of tea.

No. It looks like a bad google translation.

Not really. It looks like 3 sentences in one. What do you want to say exactly?