Meanings

I really can't get the meaning of these sentences. Please explain what do these sentences mean

1. Kylie, like the Aboriginal boomerang she's named after, bounces back to us time and again. As she so memorably sang herself, "Lucky, lucky,lucky".

2. We feel we know J.Lo and Mariah Carey inside out, like particularly tiresome sisters who we would miss any family gathering in order to avoid.

3. She remains a worker and her money stays clean.

4. Kylie is that rare thing -- a proper grown-up in a vast playpen full of infants, screaming for their thrills and bowlfuls of sweets.