Dick and Stevie Moments
Side-note: Stevie's identity as Captain America is still secret, as well. How secret her identity is, however, can vary. The general public will definitely not know.
For starters, Brooklyn and Bludhaven will be next to each other, or at least close to each other.
Stevie and Dick end up working together constantly since they are in such close proximity, as well as because there are several team-ups between some of their enemies, particularly HYDRA and The Court of Owls.
I also think that they can figure out who each other is, in a similar way inspired by how Steve Rogers figured out that Bruce Wayne was Batman from his fighting style in the comic books.
In this fanfic, Dick and Stevie casually meet, maybe inside of an art store or a book store. They end up dealing with a gang or some kind of minor threat that kidnaps them as civilians. They end up fighting their way free and maybe protecting another prisoner. They both end up recognizing their fighting styles and putting two and two together.
They can also get closer as friends, eventually developing feelings and slowly getting into a relationship, which works out better since they can know every part of themselves.
There can also be interactions with the other characters. At first, the (Not) Bat-family think that Dick is maybe dating Stephanie Brown based on rumors, but are surprised when they meet Stevie. Damian and Stevie get particularly close over time.
The interactions between the (Not) Bat-family can be funny, sometimes because they don't know what to make of Stevie, sometimes because they think she's anti-feminist (ironically), and sometimes because they think she's too understanding of Dick (also ironically) and probably deserves better. For example, if Dick leaves Stevie for a while at a family dinner, they think Stevie will be upset with him, but her reaction is exactly the opposite and makes no sense to them. This can also be on top of Dick defeating an enemy and Stevie secretly protecting his loved ones depending on the threat.
There can also be fun and funny moments with the Marvel characters and the Avengers. On this side, I think it would be a mixture of everyone loves Dick, everyone loves Stevie, and being kind of overprotective of Stevie, who they view as a little sister, with a bonus of her being naive and defenseless in their eyes (incorrectly).