Space Winners by Gordon R. Dickson 1986

They were humanity's hope - the first young people selected to leave Earth for study in the Galactic Federation.

But something went wrong in deep space. Terribly wrong. Suddenly Jim Rawlins, Ellen Bouvier, Curt Harrington, and the squirrel-like Alien philosopher Peep were castaways, stranded on the Quarantined World of Quebahr - with no training, and little hope of rescue.