I doubt it is fleas unless they are housed outside. Sounds like normal behavior to me. My Ollie an Jett jump all the time, its called a binky. Ollie doesn't like being held so much so he wiggles in my arms until I put him down. My boys both scratch them selves all over, rabbits are meticulous groomers, scratching and licking every where.
What are you feeding your rabbits? That can be the cause of the poos getting stuck to the fur. Also are they long or short haired? and how offten do you groom them?