Often, in 'construction Edward fanfic', there is the theme of perseverance. Construction projects are full of obstacles, and Edward has to keep going. There could also be themes related to the community. For example, if he's building something for the community, how the community responds and supports or challenges his efforts. It can also include themes about the aesthetics of the construction, Edward's vision for making the building not just functional but also beautiful.
One common theme is friendship. Despite their differences in the original story, fanfics often explore how they can become friends or at least respect each other.
One common theme is family. Since they are part of the Cullen family, stories often explore their roles within the family structure and how they support each other as family members.
Love is a very common theme. Bella's love for Edward is what usually drives her to save him. It shows the power of love in the face of danger.
The theme of self - discovery also frequently appears. As Bella gets closer to Edward and the vampire world, she discovers more about herself, her desires, and her capabilities. This is often explored in great detail in many bella dn edward fanfics.
One common theme is the idea of trust. Given their different backgrounds and initial distrust in the original story, fanfics often explore how they build trust with each other. For example, in many fics, they have to rely on each other during dangerous missions.
One common theme is friendship. Many fanfics explore how Oswald and Edward can become friends despite their differences. For example, they might start off as rivals but gradually learn to trust and rely on each other.
One common theme is the struggle between good and evil. Edward represents the more 'good' side, while Envy is often seen as 'evil'. Their relationship then becomes a battleground for this internal and external struggle.
Redemption can also be a theme. They both have made mistakes in their journey, and fanfics may explore how they try to make up for those mistakes. They might seek forgiveness from each other or from the people they've wronged, all while strengthening their bond as brothers.
Common themes include the power of love, of course. Their love is so strong that it can overcome many difficulties in the fanfics. Another is the concept of identity. Bella has to figure out her place in Edward's world and vice versa. And there's the theme of loyalty. They are extremely loyal to each other in most fanfics, and this loyalty is often tested in different ways.
One common theme is innocence. Since it's about baby Edward, his innocence is often explored. How he views the world without the full understanding of the harshness that will come later.