Usually, you can add an infant after ticketing by calling ELAL.
Am trying to get this done now. So far Alaska says it's added on their end, but "their international partners require that an additional seat be purchased for the infant" which of course is not true as Qantas books infants for no charge and no problem. Elal says they can't touch it as it comes through as a travel agent ticket and only alaska can add.
Any ideas? Also, can I expect that they'd be able to work this out at the airport?