Sentences for a check

Dear All:

1)
How should one write the question sentence which "Yes, there is. There is a hippo over there" reply to?

- Is there a hippo over there?
- Are there any hippos over there?

I think both are right, but some Taiwanese tutors(*1) and teachers(*2) on a Taiwanese-BBS said that the second is wrong.
Is it so?

(*1) Most are undergraduates.
(*2) I am not sure how many are formal teachers in school.

2)
Given a picture in which there is a desk, and under the desk, there are a cat, a ball and a box.
The question is "What's under the desk?" and the key answer is "There are a cat, a ball and a box."
But what's wrong with "There are the cat, the ball, and the box"?
I would read it as "the cat (in the picture), the ball (in the picture), and the box (in the picture)" ...
Will you, as an English teacher, cross it out?

3)
Well...I wonder whether or not I should capitalize the first letter in the first world if I quote a complete sentence.
I had some hesitation just now when I typed those quotes above.

Thank you.