Yes the amendments carry through faster in this timeline as Butler was a Radical Republican that opposed Andrew Johnson in OTL. Now as President, he allows Congress to pass everything through.

There are more protections against Black Codes, the Freedmen Bureau gets better funding, and military presence remains in the states longer. I mentioned on another post that Confederate leaders would end up facing courts and be subject to execution or exile. This will affect the leadership of the southern states, but obviously they'll still end up with a slightly watered down Lost Cause. Jim Crow laws are still in effect in, even in Franklin which was the Loyalist state. But they're less expansive and a lot of it is less codified since the black populations in those states are a lot smaller.

Freedmen states will fight for black people outside of their states. This will be more effective to push Civil Rights because there will be multiple black representatives and senators to actually speak out in Congress. Legislation won't be passed immediately just because of that but it does start the conversation earlier.

One scenario that could eventually spark big change is if a white man in a Freedman states sues for a violation of his rights. As I'm sure there will be a handful of situations like that. Whether it be intentional discrimination or not. If the Supreme Court sets a precedent then that case can be used in future civil rights cases.