I've posted revised draft of the spec r21 (has changes to DFDL Standard Character sets per call today)
I also made corrections to dfdl:byteOrder - added missing binary booleans as one of the things byteOrder applies to, and removed sequence, choice, group from things that can carry the byteOrder property. Having done these fixes I realized this probably requires an erratum actually.
r21 is at
http://redmine.ogf.org/dmsf_files/13318