Would entering a project started before the jam break any rules? I have this unfinished game and I want to raise its popularity and give myself more reason to finish it. Most jams don't allow pre-made games and I wouldn't want to break any rules.
Cookies don't inherently relate to the theme of "chill", but if you can find a way to tie to the theme then yes, technically. Though having watermarks over images may impair your game visually.