Ellipting the main verb after modals/auxiliaries immediately followed by adverbi...

I have just read Stuart's comment here:

What is unacceptably long in speech is different from what is unacceptably long in a formal document e.g. a legal contract. On the other hand, when spoken you can use prosody to clarify structure in a way that you can't in writing, so it's not that clear cut.
The acceptable length of the intermediate chunk in the structure 'an/the + [intermediate chunk] + Participle I/II + Noun'

To follow this pattern, one would conclude that these sentences are perfectly idiomatic - so are they?

1. She must come in the morning and he must in the evening.
2. She will come by car and he will on foot.
3. Did she work lazily and did he happily?
4. She can arrive in Paris by five and he can in London by seven.
5. She didn't take the medicine after meal and he didn't before one.
6. You may take the interview remotely and he may in person only.
7. He shouldn't swim in the river in the way that he should in a swimming pool.

What style would these carry?

As to prosody, isn't ellipting the main verb marked by a slight pause and change of pitch?

They aren't idiomatic, because you're eliding verbs that aren't usually elided, and you're using adverbs with them. Take your first sentence:

She must come in the morning and he must in the evening.

Contrast this with an idiomatic sentence eliding a verb:

He bathed in the morning, and she, in the evening.

The same applies for all the other examples, even the last one. The only way #7 works is by changing words. For example, this works (barely):

He shouldn't swim in the river the same way that he should in a swimming pool.