For comparison, while booking AY flights, checked out what they say about pets.
Making a dummy booking HEL-CPH, a pet in the cabin costs 60€ (~$100 AUD) and they take max two carriers in Y per flight, max two pets per carrier and one carrier only per pax. The size requirements for the carriers are tight, max height 20-23 cm only, max weight 8 kg. They are usually seated at the rear of the cabin, though in my dummy booking I was able to try that on row 7.
AY Travelling with pets
