I assume you want to remove the springs for the drum brakes , if you do not care about the springs & why would you you can pop them off with a screwdriver or vice grips ,
I have not done the Dr B+Diff conversion , so I am not familiar with how the parking brake system is handled , I would talk to Cass about that .
use a punch to twist the seal so you can pry it out & you need a driver the diameter of the seal to install the new seal , socket etc would work OK