For the record ...
I was bored on a long layover. Not tired enough to nap YET. So I researched the most junior FOs in the respective aircraft.
The most junior FO in the lower 48 can be found in ONT, barely.
ANC 400 ......... 10/15/07
ANC MD-11 ..... 07/31/07
ONT ............... 12/14/06
MIA ............... 11/01/06
SDFZ ............. 11/01/06
SDF Bus ......... 10/03/06
SDF 757.......... 08/30/06
SDF DC8 ......... 08/30/06
SDF MD-11 ..... 07/31/06
Enjoy !