Alex, still nothing concrete but it does appear that this MACR 7211 crew may have stayed together with 5 of this crew KIA 22 Aug 1944 when 42-52111 was shot down. Still not proof that 42-52111 was the plane from which Cook and McLean jumped but this may make it a more likely candidate.
MACR 7211 remaining crew members and fate (?)
2Lt Maurice J Beaucond, Jr., O-700893 (P) Later 22 Aug 1944 POW
https://aad.archives.gov/aad/record-...pg=1&rid=43380
2Lt Weldon H Jeffress, O-719850 (CP) Later 22 Aug 1944 KIA
https://www.findagrave.com/memorial/...don-h-jeffress
2Lt Sidney S Grapey, O-719850 (N) Later KIA (date of death in error likely should be 22 Aug 1944)
https://www.findagrave.com/memorial/...idney-s-grapey
Sgt William T Gibson, 34650016 (ETTG) enlistment
https://aad.archives.gov/aad/record-...=1&rid=5048892 Later KIA 22 Aug 1944
https://www.findagrave.com/memorial/...liam-t.-gibson
Sgt Oliver H Martin, 38512700 (BTG) enlisted
https://aad.archives.gov/aad/record-...=1&rid=7381653 No NARA POW record found. This might be our Sgt Martin
https://www.findagrave.com/memorial/...-holmes-martin (7 Sep 1924 to 27 Dec 1960)
Sgt Billy R Bolin, 38515825 (TG) No NARA record found. WW II Memorial, Billy Ray Bolin
http://https://www.wwiimemorial.com/...oreeID=2124523 likely our Sgt Bolin
https://www.findagrave.com/memorial/...illy-ray-bolin
S/Sgt Willard E Smith, 37657815 (WG) enlistment
https://aad.archives.gov/aad/record-...=1&rid=6827407 KIA 22 Aug 1944
https://www.findagrave.com/memorial/...illard-e-smith
S/Sgt Frank A Johnson, 37666953 (WG) enlistment
https://aad.archives.gov/aad/record-...=1&rid=6836075 KIA 22 Aug 1944
https://www.wwiimemorial.com/Registr...oreeID=2101161 and
https://www.findagrave.com/memorial/...rank-a-johnson