Kind of late to the discussion, but I can add some info to the issue of the 40-mm armament of the CLEVELAND class.
First off the decision to install twin 40-mm mounts on the fantail wasn't decided in 1943. It was made early in 1945. Not that it wasn't discussed before that, just that the decision to "actually" relocate two existing twin mounts was made more to counter the kamikaze threat.
The CLEVELAND class like most USN warships early in the war went through a steady "authorized" increase in 40-mm armament until mostly settling to the ultimate number in mid-1943. That number was limited by space available and top-weight (and crew space) concerns on all warships. The kamikaze threat late in the war caused a revisit to AA armament. In the case of the CLEVELANDS there wasn't much that could be done to increase the number of 40-mm barrels.
CLEVELAND class "authorized" 40-mm increased as follows (some of these lasted for only a short time);
Eight 40mm; Four twin 40-mm mounts (CLEVELAND was the only one completed to this)
Twelve 40-mm; Two quad and two twin 40-mm mounts
Sixteen 40-mm; Two quad and four twin 40-mm mounts
Twenty 40-mm; Four quads and two twin 40-mm mounts
Twenty-Eight 40-mm; Four quads and six twin 40-mm mounts ... authorized on 29 April 1944 (This was the ultimate 40-mm armament, the only change made was to relocate the midships twin 40-mm mounts, located between the two quad mounts, to the fantail giving a better field of fire and much better coverage aft.)
If you look at the class in the ORDER they were commissioned/completed, then you will find that they completed in the following configurations. The earlier units were brought up to the then "standard" during any overhaul/major repairs. Also the "round-faced" units had other issues that limited their armament.
The original "round-face" bridge units were the first commissioned;
CL-55 CLEVELAND -- 15 June 1942 -- 4x2-40mm mounts (8-40mm)
CL-56 COLUMBIA -- 29 June 1942 -- 2x4 & 2x2-40mm mounts (12-40mm)
CL-57 MONTPELIER -- 9 September 1942 -- same
CL-58 DENVER -- 15 October 1942 -- same
CL-60 SANTA FE -- 24 November 1942 -- same? may have been completed with 12-40mm, but quickly went to 2x4 & 4x2-40mm (16-40mm)
CL-62 BIRMINGHAM -- 29 January 1943 -- 2x4 & 4x2-40mm mounts (16-40mm)
CL-63 MOBILE -- 24 March 1943 -- same
The "squared-face" bridge units were next;
CL-80 BILOXI -- 31 August 1943 -- 4x4 & 2x2-40mm mounts (20-40mm)
CL-81 HOUSTON -- 20 December 1943 -- same
CL-89 MIAMI -- 28 December 1943 -- same
CL-64 VINCENNES -- 21 January 1944 -- same
CL-90 ASTORIA -- 17 May 1944 -- same
CL-65 PASADENA -- 8 June 1944 -- 4x4 & 6x2-40mm (28-40mm)
CL-86 VICKSBURG -- 12 June 1944 -- same
CL-103 WILKES BARRE -- 1 July 1944 -- same
CL-66 SPRINGFIELD -- 9 September 1944 -- same
CL-87 DULUTH -- 18 September 1944 -- same
CL-104 ATLANTA -- 3 December 1944 -- same
CL-91 OKLAHOMA CITY -- 22 December 1944 -- same
CL-67 TOPEKA -- 23 December 1944 -- same
CL-105 DAYTON -- 7 January 1945 -- same
CL-101 AMSTERDAM -- 8 January 1945 -- same
Units completed with the fantail twin 40-mm mounts:
CL-82 PROVIDENCE -- 15 May 1945 -- same (but with two twin mounts relocated to fantail)
CL-92 LITTLE ROCK -- 17 Jun 1945 -- same
CL-102 PORTSMOUTH -- 25 June 1945 -- same
CL-83 MANCHESTER -- 29 October 1946 -- same
CL-93 GALVESTON -- Suspended 24 June 1946 -- same
From PASADENA on all units were commissioned (one suspended) with 28-40mm guns. The last five units ... PROVIDENCE, LITTLE ROCK, PORTSMOUTH, MANCHESTER, and GALVESTON (suspended basically complete and mothballed ... not commissioned as a gun cruiser), had two of the twin 40-mm mounts relocated from amidships to the fantail. Other units had this same upgrade, most during post-WWII refits. Some units went into mothballs without having the two twin 40-mm mounts relocated to the fantail. DrPR appears to have a complete listing of units with the fantail twin 40-mm mounts.
I have not looked up the actual authorization date for relocating the twin 40-mm mounts to the fantail, but it likely was during early 1945 during the Anti-Kamikaze evaluations.
USS MANCHESTER (CL-83) was the only CLEVELAND class unit to receive 3-in RFG mounts in place of the 40-mm armament. By the time the Korean War started, she was the only CLEVELAND class cruiser still in commission.
Oh ... and for DrPR, I do have a photo of USS DULUTH (CL-87) with the fantail twin 40-mm mod after her late 1946 overhaul. Plus, in looking at TOPEKA's record, she was active until 1949, so she likely also had the fantail 40-mm mod done.

Ahh ... This cropped view from a 19 May 1955 photo of mothballed cruisers at Philadelphia Navy Yard Reserve Basin shows a couple of more of your list of unknowns as having the fantail twin 40-mm mod done by then ... USS MONTPELIER (CL-57) and USS HOUSTON (CL-81). Another fuzzy photo shows a few more CLEVELANDS, one without the fantail twin 40-mm mounts ... it has to be USS DENVER (CL-58) because the other units starting with a "5" not accounted for is COLUMBIA (CL-56) known to have had the fantail mod ... leaving DENVER as the only one of the CLEVELANDS at Philadelphia that doesn't have the fantail twin 40-mm mounts. Note that MONTPELIER has the "authorized" numbers of 40-mm mounts, but that the layout differs from the Square-bridge CLEVELANDS.

Well another piece of the puzzle. I sorted through DANFS and came up with a list of where all 29 of the CLEVELAND and FARGO (units marked w/*) class cruisers were berthed after mothballing as of 1951.
At Boston Naval Shipyard;
CL-82 PROVIDENCE
CL-105 DAYTON
At Philadelphia Naval Shipyard;
CL-55 CLEVELAND
CL-56 COLUMBIA
CL-57 MONTPELIER
CL-58 DENVER
CL-81 HOUSTON
CL-93 GALVESTON
CL-102 PORTSMOUTH
CL-103 WILKES BARRE
CL-107 HUNTINGTON*
At New York Naval Shipyard;
CL-92 LITTLE ROCK
CL-106 FARGO*
At Puget Sound Naval Shipyard;
CL-60 SANTA FE
CL-63 MOBILE
CL-65 PASADENA
CL-80 BILOXI
At San Francisco Naval Shipyard;
CL-62 BIRMINGHAM
CL-64 VINCENNES
CL-66 SPRINGFIELD
CL-67 TOPEKA
CL-86 VICKSBURG
CL-87 DULUTH
CL-89 MIAMI
CL-90 ASTORIA
CL-91 OKLAHOMA CITY
CL-101 AMSTERDAM
CL-104 ATLANTA
Then once she was decommissioned in 1956, MANCHESTER (CL-83) was also berthed at SFNSY
The reason I went through this exercise is that I have come across aerial survey photos of many Naval Shipyards during the 1950s. In many of the images I have scanned, I can't ID individual ships, but I can ID ship types and even classes. In this image cropped from a May 1952 photo, I found all eleven of the CLEVELAND class cruisers berthed at SFNSY. Note that all eleven have had the 40-mm fantail mod accomplished. So no need to ID individual units. So after all this, the 1955 photos of Philadelphia show that only DENVER (CL-58) is known to NOT have received the mod and that the last remaining "unknown" unit is BILOXI (CL-80) which was berthed at Puget Sound Naval Shipyard, which I don't have any yard photos of. Since BILOXI was decommissioned fairly quickly after the war, she may not have received the fantail mod prior to being mothballed.
