Perhaps there's a plot against Harry by some dark forces, and the Potters believe that only they can protect him properly. They might think that the people who have been taking care of Harry so far are not equipped to handle the new and more dangerous threats. Also, it could be that the afterlife in the wizarding world has some rules or opportunities that allow them to try and get Harry back into their family fold. They could have been given a second chance, so to speak, and are eager to take it.
One common theme is acceptance. Since Harry and Draco were rivals, their son often has to face the issue of being accepted in a world that still remembers their past enmity. Another theme is identity. He has to figure out who he is, being the son of two very different wizards.
Yes, there are quite a few. Some explore the unique dynamic of Draco being Harry's son in a world where the wizarding world has changed significantly. It often delves into how the two would interact in a family setting, with Harry as the father, and how Draco would grow up with such an unexpected family background.
Yes, they might. Just like any other group of people, those who identify as Blacks or are part of the Potter family name (if we assume there are real people with that name) could be fans of the Harry Potter series and thus read fanfiction. Fanfiction offers a wide range of interpretations and extensions of the original story, and anyone with an interest in the magical world of Harry Potter could be drawn to it.
One possible motive could be that the Potters discovered some dark plot by the Malfoys involving Harry. Maybe they found out that the Malfoys were planning to indoctrinate Harry into their pure - blood supremacist ideology against his will. So, to protect Harry from that, they kidnapped him.
Sirius Black could also be part of it. He was Harry's godfather. He might have escaped from Azkaban earlier in this fanfic. He teams up with the Potters to rescue Harry. He could be the one who scouts out the Dursleys' house before the actual rescue operation, using his skills as an Animagus to stay hidden.
It could also be that the Potters are under some sort of magical influence or curse. In the fan fiction world, there could be a dark force at play that makes them see the twins as more important. This force might be manipulating their emotions and perception, leading to the neglect of Harry.
Yes, there are some out there. Some explore the complex relationships that would form if Harry and Draco were Snape's sons. It often delves into how Snape would handle having these two very different boys as his sons, and how it would change the whole Hogwarts dynamic.
One common theme is identity crisis. Draco, being Harry's son, would struggle with his identity as a Malfoy and also as Potter's son. Another theme could be acceptance. How the wizarding world accepts this strange new family situation. Also, family dynamics, like how Harry and Draco would bond or argue as father - son.
Well, there are a few. In these fanfictions, the character development can be really fascinating. Draco as Harry's son might struggle with his own identity, being part of two families that were once at odds. It can also lead to new storylines about friendship and rivalry within Hogwarts, as he's related to such a famous figure like Harry Potter.