Solution:

Mount Everest

(discovered or not 'Mount Everest' will be highest)

Solution:

Breakfast and Lunch :-)

Solution:

A Telephone

Solution:

Each word rhymes with its numeric position in the list. (e.g. 'gun' rhymes with 'one', etc.)

Solution:

Mushroom

Solution:

Thank you (10Q)

Solution:

The Letter 'V'

Solution:

Brazil (BRAZ-IL)

Solution:

Because he want his new year to start in a cool way

Solution:

They're both in the middle of wa'T'er