Air New Zealand international flight - over the limit checked-in baggage

I'm flying overseas from Wellington in a couple of days and travelling with my toddler for the first time. Despite our best efforts and removing heaps of toys the total checked-in baggage is going about 2kg to 3kg over the limit :(

Does Air New Zealand show any lenience if the limit is just over 1kg to 2kg, considering the fact that we aren't carrying any strollers for the toddler? If not, what would be the excess weight charges at the check in counter? Can I go over the limit, say 1 or 2 kgs above the 7kg limit for carry on luggage, would that be an option? Unfortunately I'm unable to prepay for excess weight as the journey involves layovers and other airlines.

Thank you for your time if you are reading this. Please help me with your experience or suggestions and relieve my travel stress 😊