No, it's not necessary.
yes
Of course if u capitalize summer,spring,and Fall why don't u capitalize Winter 
Winter break can be capitalized, or lower case. If, on a calendar, you are writing winter break, then you would put "Winter Break". On anything else, it could be "winter break", "Winter break", or "Winter Break".
YOU CAPITALIZE THINGS LIKE SPRING, SUMMER, AND WINTER WHEN YOU USE PERSONIFICATION.FOR EXAMPLE, As I was walking down the street, Winter came and blew away my hat.
no!!
I would capitalize all of them. Catch Me If You Can.
No, "winter festival celebration" should not be capitalized unless it is part of a title or at the beginning of a sentence.
You would capitalize that word however you use it.
no you do not capitalize the names of trees
No, because its a continent but you would capitalize central america
In normal use, you would not capitalize it. It there are specific instances when it is used as a title that it would be correct to capitalize it. The Catholic Missionary Church was located in Nairobi.
Only if animal is proper noun. For instance, you would capitalize Chris Carter's nickname Animal and you would capitalize Animal from The Muppet Show. You wouldn't capitalize stuffed animal, it's not a proper noun.