A list of all WB silents known to survive as of 1999 is available
here.
Aside from the titles you listed, the following of Myrna's WB titles are known to exist:
The Caveman (run at Capitolfest in 2006)
The Third Degree (LOC)
The Heart of Maryland
A Sailor's Sweetheart
The Girl from Chicago (MOMA)
If I Were Single (LOC)
If anyone else can provide missing archival data for the above, please do!
The Midnight Taxi may exist at the British Film Institute; see
this thread.
Among her early talkies,
Evidence, Cameo Kirby, Isle of Escape, Bride of the Regiment, and
Jazz Cinderella are all presumed lost (see this
useful post).
Jazz Cinderella was a Chesterfield production, so there is a somewhat greater chance that it might have been copied to 16mm or that someone held on to a print, since smaller companies weren't nearly as strict about having prints returned.
-Harold