Unfortunately their use will be extremely limited for running third edition, except perhaps as finding kernels of plot inspiration. Pretty much all of the basic mechanical systems beyond "roll attribute + ability vs a difficulty" have dramatically changed, and the setting has undergone significant changes from 2e as well - things are more left to mystery rather than overexamined as in 2e, the non-Solar Exalted have actual places in the setting other than "inept babies sitting around as the world dies around them because only the Solars can do anything"...