A simple question before I join the jam, but does the engine used matter? I only have and am the most familiar with RPG Maker and have used it to make a dating game. It didn’t contain any combat but let’s were to say I did include combat in my VN, would it be disqualified?

You can use whatever game engine you want, for as long as you still make a visual novel. Also it would be fine to include combat and other such elements in the game.