No. Redmi 6A does not have the gorilla glass protection.
Yes, Redmi 6A does have the fingerprint scanner.
No. Redmi 6A does not have Dolby Digital sound support.
Redmi 6A has 2.0 GHz MediaTek Helio A22 quad-core processor.
The Redmi 6A is a fairly good update to the Redmi 5A, which itself was barely any different compared to the Redmi 4A. You now get a tall screen, better processor, and improved polish overall.