Been there etc.
Used a tent fly as a cover. No real need for the tent unless it looks like a wet spell is coming. Bring some form of mattress! It'll insulate you from the ground & soften the bumps. I used a high density foam camping mattress which was comfortable enough. You'll need to dig the rocks out though.
Definitely a sleeping bag. It can get pretty bloody chilly overnight there. The fly helps with this - either nil wind & keep off the dew, or reducing the breeze.
Don't bring your best clothes...