Getting the Kids to Australia

ten2six

Here's my situation. Me and my wife are already here in Australia and the kids are back home in Pinas. We are on a student visa previously and now we are granted a PR visa. The kids should be here before December 16. I am thinking of getting my mother-in-law to accompany them in getting here instead of us fetching them. Anyone ever done this? Is it hard to get a tourist visa for that reason? And my another concern is what document will they ask at the airport/immigration in Manila or Sydney because the kids are travelling with neither parent.