As/so + would be

Greetings!

As I understood from https://forum.wordreference.com/threads/inversion-in-a-comparative-clause-than-inversion.2813755/#post-14232513:
(1a) Usually the cake would be excellent, as the coffee would be. — correct
(1b) Usually the cake would be excellent, as would be the coffee. — correct

Therefore, I can also probably make the next conclusions:
(1c) Usually the cake would be excellent and so would be the coffee. — correct
(1d) Usually the cake would be excellent, as the coffee would. — incorrect
(1e) Usually the cake would be excellent, as would the coffee. — incorrect
(1f) Usually the cake would be excellent and so would the coffee. — incorrect

I infer that in such cases we must necessarily use "be" after auxiliary verbs.

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By such a logic, I made up the following sentences:
Mother asks her son John and his friend Peter: Are you hungry?

John answers:
(2a) Yes, I would be glad to eat something, as my friend would be. — correct
(2b) Yes, I would be glad to eat something, as would be my friend. — correct
(2c) Yes, I would be glad to eat something and so would be my friend. — correct
(2d) Yes, I would be glad to eat something, as my friend would. — incorrect
(2e) Yes, I would be glad to eat something, as would my friend. — incorrect
(2f) Yes, I would be glad to eat something and so would my friend. — incorrect

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John answers: Yes, I would be glad to eat something.
Peter:
(3a) As I would be. — correct
(3b) As would be I. — correct
(3c) So would be I. — correct
(3d) As I would. — incorrect
(3e) As would I. — incorrect
(3f) So would I. — incorrect

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Which of the sentences (#1a-f, #2a-f and #3a-f) are correct to you and which are not? Thanks!