Lincoln knew that it would take an amendment to the US Constitution in order to formally end slavery. He also knew that he could order the freeing of slaves in areas affected by the rebellion.
It immediately emancipated somewhere between 20,000 and 50,000 slaves.
No it did not. It emancipated zero. He had no jurisdiction in the South because the South had severed ties with the Union. It was another country. Why didn't he also free the slaves held by the Yankees in the north?