i dont know how to make non-mouse working buttons for the menu lol
You can do whatever you want, but the spirit of the jam is to make things in the style of the limitations of the original Game Boy. Two things worth noting:
The jam page does say to use the same control scheme, and mice weren't too common with the original hardware. I doubt many people would mind, but it may count against you. If you're really, really stuck and don't have time to learn, you could forgo having options and just display a "Press start to play" titlescreen so the player just has to press one button to get into the game.