> emmental
Try it on melted on a grilled sandwich/panini.
> Camembert and gouda
Again, try on a sandwich sliced/cubed on a salad, enjoy on crackers with some fruit and honey, alongside charcuterie, pickles, olives, etc. Gouda makes a good component for fondue.
> My question is is there a guide on how each cheese is best for a certain way of eating?
I'm sure googling around for "Uses for [Cheese]" will produce a lot of results for you. I recently came into possession of this book which lists hundreds of different cheeses from all around the world and information about them, including potential uses and serving suggestions. There are many such books out there.
> Can I eat cheese after its expiration date? I suppose it's bad for softer cheese or cream cheese, but I think for harder cheese like cheddar or grana padano it should be fine.
You're correct. As long as you don't notice any mold, discoloration or off-flavors it's usually okay. The harder the cheese, the less moisture and less tendency to spoil. Always wrap cheese up tightly in the refrigerator because it could absorb odors from other foods.