Not sure about their manufacturing sources, so I can't speak about "child slaves".
Etnes, but they might be a bit on the pricier side. I can ususally find something that looks decent and fits my feet for around 70$ US if I keep an eye out on the "Sales" page.
I've had three pairs in something close to 10 years so they're pretty long lasting. A few of the styles are "Vegan" friendly.
One note, you'll need to choose a size that is ONE FULL SIZE LARGER than what you normally wear. If you wear a US size 8, you will need to look for size 9.