William is older, and so ahead of Harry in the line to the throne.
His eldest son, William. Prince Harry his 2nd son is 3rd in line to the throne.
Kate Middleton will become a princess when she marries Prince William. If William becomes king, Kate would then become queen. If Queen Elizabeth II abdicates the throne to Prince Harry however, Kate will remain a princess. This would seem unlikely considering William is in line to the throne before Harry.
Currently, the next royal in line of succession is Queen Elizabeth's second oldest son, Prince Andrew, the Duke of York.
Prince William is second in line to the throne, Prince Harry is fifth in line.
If Prince Charles dies, Prince Andrew will not become King because Prince Charles has two sons, Princes William and Harry. As Charles is heir to the throne, if he dies, his eldest son William will become heir.
It is likely that Prince William will become King after his father, Prince Charles.
Prince George (born July 22, 2013) is third in line. As of 2016, the line is through Prince Charles (oldest son) to Prince William (oldest son) to Prince William's children (George and Charlotte). They would be followed by Prince Harry (William's younger brother), then Prince Andrew, Duke of York (younger brother of Charles) and Andrew's daughters Princess Beatrice and Princess Eugenie.
If Prince William has a son while his grandmother the Queen is still alive the child will take Prince Harry's place as third in line to the throne. Probably after many years he would become Prince of Wales and eventually King.
Yes, she could be. If Prince William has a daughter, she will be next in line to the throne, after him, and before William's brother, Harry. However she will be heir apparant only, as while William lives, he could possibly give birth to a son who would supplant her on the line of succession. Assuming William becomes king, and dies or abdicates with only female heirs, then the eldest of these will become Queen.
Prince Harry is currently fifth in line to the throne so it is very unlikely that he will become King, but not impossible.
Yes then his children
If Prince William is alive after the death of his Grandmother Queen Elizabeth II and his Father Prince Charles he will become King.