If one of queen Victorias uncles produced an heir after her coronation would she have had to relinguish the crown to this "rightful" heir?

No, because even if one of the uncles had had a child, they would not have been ahead of Princess Victoria because her father was the oldest brother of William IV whose own children predeceased him.

But if there had been an elder brother who had a subsequent child, it would have caused constitutional questions that have never had to be addressed. I suspect Queen Victoria would have had to step aside but there would have been 9 months to create new rules to deal with the situation.

No, because her father was the oldest of the younger brothers of William IV. Her surviving uncles were all younger than her father had been, so that made her the first in line to the throne after her father's death and after William became king.

At the time of Victoria's birth in 1819, her Uncle George (King George IV) was on the throne. His only child had died in 1817, so his younger brothers William (later William IV) and Edward (Victoria's father) were 1st and 2nd in line to the throne. William had no surviving legitimate children, so Victoria, as Edward's only child, was 3rd in line, but she moved up to 2nd when her father died in 1820, when she was only 1 year old. Then, on George IV's death in 1830, when her Uncle William became king, she moved up to 1st in line.

Therefore, even if she hadn't already been crowned, no child of her surviving uncles -- all younger than her father, as I said -- could ever have had a better right to the throne than she did. She could have been knocked out of 1st place during William's reign only by the birth of a legitimate child to him.

A coronation, incidentally, is only a formality and isn't actually required. Victoria was Queen from the moment her Uncle William died. She didn't need to be crowned.

No. Victoria was the rightful heir! She was the heir to her father, her uncles in line AFTER her.

What rot. She DID have an uncle and he DID have a son but they became the kings of Hannover because Hannover did not have female succession as England had. She did not inherit Hannover but did inherit England for this cause.

No once crowned she would be Monarch for life.

NO, once crowned she was the "rightful" monarch.

No

No. All her surviving uncles were younger than her father, which meant they were behind her in the line of succession.

No,she was queen, no body else could claim the throne.