Riddles...

Q #1:
What kind of coat can only be put on when wet?
Q #2:
What letter comes next in this sequence?
J F M A M J J A S O _
Q#3:
What's full of holes but still holds water?
Q#4:
What building has the most stories?
Q#5:
Why is an island like the letter T?
Q#6:
Pronounced as one letter,
And written with three.
Two letters there are,
And two only in me.
I'm double, I'm single.
I'm black, blue, and gray.
I'm read from both ends,
And the same either way.
What am I?

If you want to guess or answer these questions, please click "comments" and write a comment. :-)
Thanks!