Not entirely sure, but I think Disc 9, Track 1-3 is an example for a session which is not available elsewhere (which would mean "No" to Q1):
Disc 9, 1-3: Don Senay (voc); Thad Jones, Louis Mucci (tp); unknown (brass); John LaPorta, Julius Baker (woodwinds); Billy Taylor (p); unknown (harp); Jackson Wiley (cello); unknown (strings); Milt Hinton, Fred Zimmerman [Charles Mingus?] (b); Joe Morello (d, perc) or unknown (perc); Alonzo Levister (arr)
The Edge Of Love (2:48) (Baker/Ables/Goode)
Makin' Whoopee (2:38) (Donaldson/Kahn)
Fanny (3:01) (Rome)
http://mingus.onttonen.info/details/fantasy/debut.html
(upon first sight, this concerns Disc 9, 1-4, 4 is on the small Debut Records Story Box though, and the final track on Disc 12)