Boeing start No. 2 first
I asked same question many years ago, why #2 engine (#4 on the 747, 744 ) started first.
I was told at the time, it was for 2 reasons.
1, As previously discussed this engine drives the hydraulic pump that supplies the primary braking source,
2, The "essential" power BUS normal source also comes from this engines'
generator. ( Not quite true in the 767)
When you look at the A330 the Primary and Alternate green and blue hydraulic brake source come from Engine 1, as well as the normal Essential power supply is also from Engine 1.
Does the A330 start engine 1 first??