In the ITC FAQ the answer is yes. In the GW 2016 FAQ nothing is said about this question.
I play yes, giving Ezekiel 5 attacks (including Book and Boltpistol), 6 on the charge.
See it as a banner, the deathwing company banner bearer also gets +1 attack. Ezekiel is also inspired by carrying the book of Salvation.
- A unit containing Belial that uses the Gate of Infinity psychic power to Deep Strike does not scatter.
- Ezekiel does benefit from the Book of Salvation wargear, effectively giving him 4 attacks.
- A model with the Ravenwing special rule includes the reroll to their cover save in determining which of their saves is the best. For example, a rerollable 4+ Jink save is better than a 3+ armor save.