The Civil Rights Movement gives us clear examples of all of these stages of a movement.
For legalism, you can point to any number of court cases. The most famous of these, of course, is Brown v. Board of Education which was decided in 1954. This was the last major legal decision of the Civil Rights Movement.
For activism, you have any of the protests that are such a famous part of the movement. You have the Freedom Riders and the sit-ins in Greensboro. You have the March on Washington. You have the marches in Alabama and elsewhere that attracted such violent reactions from the authorities.
Finally, for fragmentation, you have the splits between the more moderate activists like Martin Luther King, Jr. and the more radical activists like Stokely Carmichael or even the Black Panthers.