The DeepMimic project currently offers no way to import custom reference motions. This is shown in DeepMimic issue #23. This project contains a list of projects which aim to transfer animation data from various file formats into DeepMimic Motion files. Motion files can then be used to Train DeepMimic skills.
sloganking/DeepMimic-Animation-Conversion
Contains a list of projects which convert animations to a format DeepMimic can understand