The length of the DBFZ story can be subjective. It includes multiple arcs and character developments, which can make it feel quite lengthy for some players, while others might breeze through it.
Yes, it is. DBFZ Story Mode has many characteristics of a visual novel. It presents the story through a series of visual elements like character illustrations and backgrounds, along with text - based dialogue and narrative, which are typical features of a visual novel.
I don't have the exact number off the top of my head. But you can usually find that information on dedicated gaming wikis or by reaching out to the game's developers or community managers.
One idea could be a crossover with the Dragon Ball Super universe and the DC Comics universe. Zamasu could team up with Darkseid, believing they share a similar view of bringing 'order' to their respective realms. Another idea is a crossover with the Naruto universe, where Zamasu tries to impose his will on the ninja world, facing off against powerful shinobi like Naruto and Sasuke. Or perhaps a crossover with the Star Wars universe, with Zamasu as a Sith - like figure, trying to gain control over the Force.
Well, the length of the DBFZ story in chapters can vary. Sometimes new chapters are added, and it's hard to give a fixed number. Maybe you can search on dedicated fan forums for the latest info.
One interesting Zamasu fanfic could be about his origin story in more detail. It might explore his early days in the Kaioshin realm, his training, and how his ideology started to form.