N21 #5 OCTANE OZZIE. This one looks like a product of the CAC Fort Worth PR machine
N21 #8 OLD BERTHA, B-24E at Willow Run by the looks of it
N21 #8a OLD FAITHFUL II. B-24J-FO 42-50658 389BG 566BS
N21 #9 OLDE MOTHER HUBBARD, 5BG, another OKC mod
N21 #10 OLD GREY MARE, Stateside, a hand-coloured image on a postcard.
N21 #11 OLD GREY MARE again, included as a reference for the image below, notated as "Ist B-24 at Keesler Field", suspected to be 41-23xxx.
N21 #12 OLE GUINEA PIG. I have my doubts about this one - note that it is the same picture as above and another hand-coloured postcard with an altered name - neither of which may be real!
N21 #12a OLD KING SOLOMON Jr 376BG. Early model B-24D (Note position of pitot) and may even be a 're-cycled' HALPRO aircraft - see fixed MG at base of Greenhouse.
N21 #13 OLD TAYLOR
N21 #14 OLE BOOMERANG, an F-7A of the 4th PRS
N21 #15 OLE BOOMERANG, 460BG
N21 #15a OLE HERRINGBONE. A photo received much later now reveals this to be in the US and I believe it may be a B-24E rather than a B-24D