what does this picture(rebus) riddle means ?

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?

A spy was in Canada trying to steal insider information on how to set up new Maple Syrup factories in their country. He was introduced to the operations manager of the biggest factory in Canada. However, the manager was suspicious and decided to test him with a question before he trusted him. So he asked, “What would you be sure to find in the middle of Toronto?” The spy thought fast and came up with an answer for the manager. What was his answer?

A plane crashed between the border of Mexico and America. Where do you bury the survivors?

A 52% bias toss for head using the 51% tail bias coin was done to obtain a fair result.

Can you find how bias is the floor in this case?

What number does the below three word/phrase identify and why?
1. Deck
2. Year
3. Singing in the Rain

They are three errirs in this question. Can you find them?

A girl is twice as old as her brother and half as old as her father. In 50 years, her brother will be half as old as his father. How old is the daughter now?

You see a boat filled with people, yet there isn’t a single person on board. How is that possible?

What has one eye, but can’t see?