Fangames are allowed as long as all the assets are yours. And of course, this isn't legal advice, but some IPs prefer no fanworks, so it's recommended you look out for that. But yeah, totally allowed for this jam!
Ah gotcha, and also thank you for reminding me about the IPs. I double-checked with my friend again and she said as long as it's not for commercial use (which I don't plan to), there should be no problems.