This may already have been mentioned, but it occurs to me that the "Poor Howard dead and gone" lyrics may have come from the
"Pompey is dead" family of children's game songs.

Those songs originated in Great Britain and were known to 19th century (and earlier?) African Americans by the name "Old Ponto Is Dead" and other similar titles.

See page 1936 of the 1925 book "One The Trail Of Negro Folk Songs" by Dorothy Scarborough and Ola Lee Gulledge for a version of that song as well as a description of its performance activity. That page is available on http://books.google.com/books?id=Ys3T_6clobAC&pg=PA136&lpg=PA136&dq=pompey+is+dead+and+laid+in+his+grave&source=bl&ots=kxEiLw-cK