FYI I wrote an article for NSMD (Winter 2007) about the history of brushes including photo's of some rare examples, one dated 1913.
Apologies about being late getting back here.
Wow, excellent photos! I'll have to see if I can get a back issue of NSMD (I think there's at least one U.K. drum shop that sells them).
In that last photo, is that broom straw or something?! (the one with brown looking 'bristles').
510, glad you found the additional info interesting!