One idea could be to focus on Bardock's perspective before his fateful battle. Maybe explore his thoughts about his son Goku being sent to Earth and his own impending doom. He could have some premonitions about Goku's future role in saving the universe.
Definitely include Bardock's last stand. His heroic yet doomed battle is a crucial part of the Saiyan lore. It could be written in great detail, with Bardock using his full power against Frieza's forces.
Goku does reach a state of immense power in the manga that rivals that of a God of Destruction. However, the specific title and all its implications might not be straightforwardly assigned to him. It's a complex development within the story.
I haven't actually read this specific 'piccolo and gohan lemon fanfiction', but generally, in fanfictions involving these two characters, it might explore their relationship in unique ways. It could be about their friendship evolving, or perhaps their teamwork in new and unimagined scenarios within the Dragon Ball universe.
Gohan would be really surprised, but being the kind - hearted person he is, he would try to understand and help out. He could offer to train with them in a more gentle way to keep them fit during the pregnancy. Piccolo would be more of a silent observer, but still be there in case of any threats.
Bulma could be a catalyst. She's very intelligent and might come up with some sort of device or plan that could change Goku Black's perspective. Maybe she creates a machine that can influence his mind just enough to make him start to question his evil ways.
Sure. Fanfiction often takes the existing characters and situations and twists them. For Harry and Dudley, it could start with a shared experience that makes Dudley realize Harry isn't so bad. Maybe they get caught up in a magical adventure together outside of the normal Hogwarts - related stuff. This common experience could break down the barriers between them and start a friendship.
Sure. Fanfiction often takes existing characters and gives them new storylines. Maybe in some fanfictions, a situation arises where Harry and Snape have to work together towards a common goal, like saving Hogwarts from a new dark threat. Through this shared experience, they could come to respect and like each other, thus becoming friends.