We already know that P-51 #1 (the one closest to you) is Max Hoffman's 44-74832 N6310T. The 2nd was CF-USA, Don Plumb 44-74850. This P-51 crashed 1975 in Texas (Plumb k).
The 4th P-51 is 45-11586, N5324V owned by Walter Oakes based in DuPage, IL. Aircraft was restored as "Death Rattler", N51HT and owned by Harry Tope who was killed in this P-51 in 1990. The 5th P-51 is 44-74756, N2112 owned by Bill Ross in '67 also based in DuPage, IL. This aircraft was later registered as N68QF, Ken Bernstein, race #33, "Miss Susy Q". Bernstein crashed this aircraft in Mojave 1976 (Bernstein k). The 6th P-51 is not a P-51 but a Fairey Firefly TTMk6, CF-BDH from Canadian Warplane Heritage. Perhaps lost in an accident in 1977?
T J Johansen
Having looked at this photo again, and with the added knowledge of just having seen a different photo of this line- up I can add that the 3rd P-51D is N469P which crashed in Atlanta, GA on April 8, 1973. The fifth Mustang is not Bill Ross N2112 but rather N2251D after being rebuilt following the oxygen- bottle explosion at Oshkosh 70.