For how long my child visa will last for?
Child visa (Subclass 101) is a permanent resident visa of Australia and lasts forever, means after obtaining this visa the child can stay permanently in the country.
Can I study in Australia after obtaining this visa?
Yes, a child can work in Australia after this Family visa has been allotted to them and even can work complying to the Australian laws and regulations.
Can I apply for this visa while I am in Australia on tourist visa, visiting my parents?
As it is an offshore visa, the child applying for it must be outside of Australia when they the application and when the visa grant is given to them.