As long as you follow the rules of the jam, as per this page, submissions can range from different themes.
In general, please refer to the Otome Jam page rules:
- Female Protagonist (protagonist can be choosable but a fem option must be available)
- Romance (You have to end up with one of the characters in some way romantically)
- Male Love Interest(s) (Female, nonbinary, and other ones optional but not necessarily included, the focus is still at least having one male love interest)
It is the half-way point, so I'm not really sure if it's wise to suggest starting with only a month of time left.