Needle nose pliers are the way to go for those, you need to grip the screw very tightly. It's probably worth using the needle nose pliers as a start to get the screw loose.
The bluetooth antenna (the one at the back of the case) is also equally tight and is a very soft headed screw.
Also when you are trying to remove these screws, make sure the screwdriver fits the head of the screw very tightly. It has to be really precise otherwise you'll round them out.
Apple stupidly suggests "jewellers screwdriver" for some of these screws, but that will never work.