Yes, there might be. Fanfiction often explores various scenarios, including characters getting pregnant. You can try searching on fanfic websites like Archive of Our Own or FanFiction.net to find such a story.
Maybe it could start with an unexpected event that leads to Zari's pregnancy. For example, some kind of magical mishap. Then Constantine, with his knowledge of the occult, tries to figure out how this happened and what it means for their future.
In certain comic versions, Zari Tomaz is indeed presented as Muslim. This aspect often adds depth to her character and influences her story arcs and decisions.
There were four reasons why Constantine was not filming for the second season. First, the lead actor, Keanu Reeves, had a conflict with another movie, The Everlasting, which made it impossible to continue filming for the second season. Second, the original investor, Warner Pictures, was not satisfied with the box office of the first movie, so the producers did not want to continue investing. Third, the director was hesitant, which might be one of the reasons why the second season was stopped. Finally, no one was willing to continue investing in the series. Although there were reports that Constantine was expected to be resurrected for the second season, there was no definite news at the moment.
In some comic storylines, Constantine's sexuality is ambiguous or not clearly defined. It depends on the specific interpretation and version of the character.