Since the use of "Jr." and "Sr." is usually to help distinguish between a father and son, both of whom are still living, the son can drop the "Jr." after the father dies, if he likes, or he can keep...
Nobody knows who Goku jr's parents are but his grandma is pan. There is only one parent know to be Vegeta jr's mother and that is known al bulma jr. look in the last episode of dragonball gt and...
In the last episode of dragonball gt, near the end of the pisode, you see them fighting in the world tournament. You also can see Goku jr in the dragon ball gt movie "A Hero's Legacy."