Attribution of authorship within undergraduate group project reports
FWIW, I mocked up some sample reports--some having the byline style and some having the footnote style--and I've decided upon the byline style. I disliked more the presence of footnote numbers at the end of the chapter subtitles compared to the bylines.

Noting that the same student(s) could author contiguous subsections within the report, I think I'll use bylines only to indicate a change of author/contributor rather than requiring a byline within each and every (sub)section within the GROUP report.

The definitions for AUTHOR and CONTRIBUTOR I've settled on are those provided in the IEEE Publishing Policy and Ethics manual. The IEEE manual was chosen simply because the students I instruct/manage are electrical engineering majors, or computer engineering majors, or both, and the IEEE's style guides are relevant to both majors.