Can you replace the question mark with the correct number?

I came first on earth but second on the heaven.
I also came twice in a week but found just once in a year.
I stay away from months but you can find me in February.

What am I?

Here is a mathematical expression that also secretly tells a movie name. What movie is that?

When I got four, I have it none.
When I got two, I have it some.
When I got none, I have it all.

What is it?

I have branches, but no fruit, trunk or leaves. What am I?

On a special event at the prison, 5 prisoners John, Jacob, Krist, Tang, and Dang given a chance to go to a sauna and can bring one thing with them.

Following are the things that the prisoners bring with them.
John: A soda
Jacob: Thermos
Krist: Book named "How to kill"
Tang: A Walkman
Dang: Harmonica

Since it is a Sauna, no one can see each other. After a while When the steam is switched, Tang was found dead and there was blood all around.
J Bond was called and he instantly come to know who can be the murderer. How?

Solve below popular number sequence
314 159 265 358 979 323 846 ?

What number comes next in this sequence:
7 8 5 5 3 4 4 _

Use only one mathematical symbol and all numbers (0-9) to get a sum of 99

Given that

(78)^9 = 6
And (69)^4 = 11

Can you find out

(99)^2 =?

(Note: This is Logical, not Mathematical)