Is this position legal?

Bf2 -> Bg2 makes it slightly less boring.
c4 -> c6 + removing the Bc5 makes it almost a real problem.

The board is not upside down chessgrandmaster.
Then it is not legal, for black cannot retract the Q check.

not legal either way
Incorrect - if the board was upside-down, black could have just promoted to Q.
not legal either way
Incorrect - if the board was upside-down, black could have just promoted to Q.
Then he is in check by 2 pawns and a queen.
Yes, he can castle queenside