You may know that The Emancipation Proclamation applied to
only southern blacks. Northern slaves were still not free!
And the South was not under control of the US, so it freed no one, technically.
No, because that would require a constitutional amendment, something Lincoln pushed for but couldn't get through congress until the Republicans gained a supermajority in the 1864 election. But as a war measure, he could free the slaves in the area under rebellion. You're criticizing him for following the law.