No. Oppo A3s does not have the Corning Gorilla Glass protection. Ideally, to protect the display, you should use tempered glass over it.
No. Oppo A3s does not have the fast charging support. However, the phone comes with 5V charger.
No. Oppo A3s is not a waterproof mobile.
Yes, Oppo A3s does have the GPS support.