I think 3 days for the salad and cheesecake would be fine if your fridge is pretty cold. The only things I don't like as leftovers are cut tomatoes, lettuce, or meat if you microwave to reheat. But all of that stuff in the salad sounds like it wouldn't spoil easily. Look at each ingredient and think how long you'd let it sit by itself in the fridge and then throw it out when the ingredient that goes bad the fastest would be past date. And things like vinegar and sugar are actually natural preservatives so the cheesecake should be totally fine for longer since it's got so much sugar in it.