One common theme is the exploration of the unexpected. Mpreg is not a common occurrence in the original universes of Harry and Edward, so these fanfictions often deal with how they handle this sudden and strange situation.
Often, themes in such fanfictions might revolve around relationships. Given the mpreg aspect, there could be a focus on how the characters deal with an unexpected pregnancy. For example, how Harry or Edward handle the physical and emotional changes, and how their relationships with other characters are affected. There could also be themes related to acceptance, both of the situation and of the new life that's coming.
Well, I'm not a huge fan of mpreg fanfictions myself, but you could try looking on some major fanfiction websites like Archive of Our Own. They usually have a large collection of fan-written stories, and you might be able to find something related to Harry Potter and Edward Cullen there.
There's also 'Unexpected Changes'. In this fanfiction, the author really focuses on the character development of both Harry and Edward during the mpreg journey. It's interesting to see how their personalities shift and grow as they face this extraordinary situation together.
One common theme is the exploration of a non - traditional relationship. Since mpreg is not a typical concept in the original lore, it allows for a new way to look at Jacob and Edward's connection.
In many of these fanfictions, Jacob's character often develops a new sense of vulnerability. For example, in stories where he discovers he's pregnant, he has to deal with physical and emotional changes that he's not used to. Edward, on the other hand, might develop a more protective side. He has to step up and support Jacob, which is different from their previous dynamic.
I'm not sure if there is a specific 'Dudley Gets Harry mpreg fanfiction'. Fanfiction covers a vast range of ideas and pairings, but this one seems rather unusual. It might exist in the extremely diverse world of fan-created works, but it's not a common or widely - known type of fanfiction. You could try searching on specialized fanfiction websites to find out for sure.
It is not appropriate. 'Lemon' is often used in fanfiction to denote sexual or adult - related themes. While fanfiction can be a great creative outlet, when it involves such inappropriate content as this, it goes against the standards of what should be acceptable in a general or family - friendly context. Even the'mpreg' aspect, while a creative take on character development, in combination with the 'lemon' aspect makes it inappropriate.
I'm not sure about its popularity. There are so many fanfictions out there that it's hard to gauge the popularity of just one. It might be popular among a niche group who are interested in the concept of mpreg and Harry Potter, but it may not be widely known to the general Harry Potter fanbase.
You can try fanfiction.net. It has a wide variety of fanfiction, including Jacob x Edward mpreg stories. Just use the search function and type in the relevant keywords.