A 'complex' sentence with tenses and words

Hi everybody,

I would like to ask you about a complex sentence.

Facts:

1. somebody (maybe a child) is doing their homework. It will be done at 11 o'clock a.m. .

2. somebody else (maybe their mother) is making lunch. It will be ready at 10:45 a.m. .

I would like to express something like:

When the homework is done lunch will be ready.

By the time their homework will be done lunch will be ready.

Till their homework will be done lunch will be ready.

Right on time he finishes the homework lunch will be ready.

It was intentional to use this order but I'm curious about the other way, too. For example (as an example of the other way):

Lunch will be the ready when s/he finishes their homework.

Are both order possible? (plus question here: can I use the word 'both' in a question like this? I haven't seen such sentences but books also don't write whether it is possible or not).

I'm curious about more possibilities if there are more equally good solutions.

Sorry for this mess. It is NOT against you, I'm just out of practice. I want to take some English lessons soon but it will be only after 0,5-2 months from here. Please ask anything and I will try to clarify my unclear sentences.

Thank you very much for every answer in advance.