Keep in mind a number of things:
1. You are concentrating on the postwar survivors' accounts (I have the relevant pages of all of them you cite except Slone) from 2nd Bn, 131st Field Artillery, the only one of the four battalions that went on to Java, sailing on (a) USS REPUBLIC to Brisbane, and (b) MS BLOEMFONTEIN to Surabaya. The important thing to remember is that the formerly unarmed and white-painted USAT REPUBLIC was by the time of the PENSACOLA convoy now the commissioned, armed, and almost certainly repainted USS REPUBLIC. If the indirect proof I offer in subsequent numbers is convincing, REPUBLIC had already been painted in naval camouflage measure and thus the lads in 2/131st didn't have to wield any paint brushes in making their vessel less conspicuous. On the other hand....
2. The members of the three other battalions, 1st Bn and 2nd Bn, 147th Field Artillery and 1st Bn, 148th Field Artillery, were aboard USAT WILLARD A. HOLBROOK, which was still unarmed (save a few MGs) and still painted her peacetime white or off-white, in which livery she had long been in army transpacific service. Thus we must rely on the accounts of guys in those three battalions, NOT the accounts of the Texans aboard REPUBLIC.
3. From ALL accounts, we must conclude that their authors wrote what they remembered most vividly: the wholesale seasickness upon encountering the huge swells outside of S.F. Bay (but from some not even a whisper of that sickness); the "old French 75s" (a canard: they were the newest model, with split trails and significantly greater elevation and traverse--but some accounts do tell of leaving their old guns behind and their introduction to this new and better model); painting HOLBROOK "battleship gray" (the 148th F.A. history chronicles it, the 147th F.A. history does not), etc. To all of these points and omissions or contradictions, go figure.
4. On page 3 of (then Lieut.) Bill Heath's HISTORY OF THE 148th FIELD ARTILLERY (he was at sea with 1st Battalion) one reads, "December 7, the commander of troops announced over the PA system that the Japanese had bombed Pearl Harbor!....But somebody must have anticipated trouble, for out came the paint brushes and paint. The red, white and blue of the once proud PRESIDENT TAFT (now the HOLBROOK) gave way to battleship gray as hundreds of "volunteers" crawled over the ship painting her from stem to stern and from mast to waterline."
Okay, I suspect some of the above is in error from rusty memory or melodramatization. I don't think that what was handed out was battleship gray, which was that almost white color once adorning the ships of the Pacific Fleet, familiar from those photos of treaty tinclads at Mare Island in the late 1930s or 1940. That color wouldn't have been much better than white, so why bother? I don't think that the captain had guys overside on bosuns chairs on the high sea (mebbe at Suva, mebbe not), IF the hull of HOLBROOK needed painting (many of the prewar USATs had black or very dark hulls; some USATs were completely "white", I THINK those with substantial troop accomodations). As far as the painters being volunteers, sure thing, Bill. Whatever, it is clear that both USAT WILLARD A. HOLBROOK and USAT MEIGS sailed from San Francisco and Honolulu in peaceful mode: no deck guns and in peacetime livery.
Take a squint at these two photos of vessels long in transpacific service, in both cases during most of the 1930s: USS HENDERSON (AP 1) and USS (ex-USAT) REPUBLIC (AP 33). Early photos of both vessels are readily found in the usual places and both were once painted white or near-white (for the naval transport, the so-called battleship gray). Just before the outbreak of war, the navy began repainting its transports in two-tone Measure 2 (or the later variant, Measure 12): a dark colored hull (either dark gray or sea blue) up to the lowest point of the main deck, then light gray on the upperworks and masts, such that the color demarcations were horizontal across the length of the ship in the so-called horizon blend. These colors were changed somewhat in the later Measure 22, but with the same guidelines in place.
Here is HENDERSON (AP 1) transiting the Panama Canal sometime in 1941, not long before war erupted.
Below is REPUBLIC (AP 33) in August 1942, about 3/4's of a year after she took part in the PENSACOLA convoy. Again note the horizon blend of either Measure 12 or Measure 22 (I don't have date specifics when these measures changed). My argument is that once the navy got their hands on this former USAT, they armed her (we know that for certain) and repainted her in two-tone naval measure.
USS REPUBLIC (AP 33); ex-USAT REPUBLIC; ex-SS PRESIDENT GRANT; in transpacific army service from ca. 1932 to 1941; commissioned USS REPUBLIC 22 July 1941; took part in the famous PENSACOLA convoy in November-December 1941; shown at P.H. 15 August 1942.
Several USATs are shown only a little later in two-tone wartime measure for all appearances identical to that of the naval transports, very likely because the army sensibly acquiesced to the navy's recommendations.