You won't be able to fly without another adult

You have to have at least 1 adult per under 2. Fare wise it's usually 10% for under 2's and 75% for over 2's. And carseats and pram should be fine, you get 20kg allowance for yourself, 10kg for each under 2 plus one piece of baby equipment per under 2 so your weight allowance is heaps considering it's only for a long weekend so you won't need too many clothes etc.
Edited by Maya