Is it ever grammatically correct to say "And you, my."

If it is acceptable to answer

I love you.

with

And I you.

which we could represent as:

And I love you.

Would it be acceptable to answer:

You’re my hero.

with

And you my.

in other words:

And you are my hero.

1. Why is the gap allowed in the first response?

2. Does this allow for gaps in the second response too?

3. If not, why not? (in relation to each gap)