Is the baby jogger second seat kit considered an essential item?

Hi Jaime, unfortunately they are not. The following are considered essential products: Car Seats, Bassinets, Breast Pumps & Accessories, Feeding Bottles & Teats, Nappies & Wipes, Baby Monitors, Swaddles and Sleep Suits and Blankets. But I would suggest calling your nearest store to see if they can help at all.
https://www.babyonthemove.co.nz/store-locations/