For game jam submissions remember that there are two pages; the itch.io page and the jam submission page.
My jam submission page notes:
List any content that was created before the jam that was included in the final submission.
In-game art is from the marketplace HOWEVER through Christen's art direction we refurbished many pieces to fit in with our cartoon shader (which we also created). Christen completed all level design and lighting elements. Additional post process effects were implemented for our water.
In addition as an online game I can prove server uptime that the game was not changed after the cutoff time. I noted on the jam submission page as well:
"During the Jam I built my own patcher for the event. My not-so-sneaky way of getting under 100 MB. Did it work? Probably not! The game will not be updated after the cutoff time and I can verify server uptime at anytime."
I will add this info in to the itch.io page.