We wouldn't have to make every character on screen 18.*
There are a lot of child and teen characters in the X-Men comics that we either have to age up, whether they are romance options or not, or not include at all. Like we can't have Illiyana/Magik show up prior to her being thrown into Limbo. The most we can do is imply that she's around.
We could have more male characters due to less spending on sex art.
We could have other characters date without the game being labeled NTR.
A female Null could be written simultaneously with the male Null since the game would focus less on dating and more on just being an X-Men life sim.
Dating could still be possible but the pool of options would likely be limited in comparison as we likely wouldn't break all of the couples up. Some of them we would because we're tired of Marvel's melodrama, others are fine. I know a lot of Kitty fans would be happy with her and Colossus actually getting married.
*A background detail that we don't draw too much attention to is that there are several students that aren't 18+. On Earth 69 Xavier's school opened up to more students several years earlier than the comics and what you see in the Fox X-Men movies.
