What are the dates of the photos showing the silver fans? I only have photos of one unit with silver fans among a number of photos of locomotives in that livery, and that dates to a visit to WA (either 1982 or 1984, I was there both years) which would be towards the end of the striped livery and around the time of the two large logo orange and blue liveries. Of course the silver fans might have appeared soon after I left in 1978 but they don't appear in my photos of 1975-78 when the livery was introduced. The one loco I have painted in the original livery without white edging does not seem to have silver fans either.
(It might be worth talking about the white edging... the gret tone of the orange and the blue were identical, so in a black and white photo the loco appeared a single colour. Since B&W was still used a lot in publications in the 1970s, the white edging was introduced so the livery was visible in B&W.)
I'm pretty sure that 3107 always had the illuminated numbers, with the numbers on both sides of the nose and rear as converted and LZ on the left as viewed when the class letters were reintroduced after the QR purchase.
One unit of interest was L 262 which was the last L overhauled before ZTR was added, after L260 and L268 in Yellow. It was painted in the orange and black but was never upgraded to LZ and became L 3110. But when I saw it in 2004, it had illuminated numbers, as you say under the marker lights, both reading "262" while above the marker lights it had dummy decal numbers (also 262).
I would be happy with number boards being painted on models of this period, since some of the numbers were not illuminated anyway.
The ATN locomotives did not have illuminated numbers when first in service in Victoria, and I hope Haskell produce a model of those since we seem to be stuck with the later version from the competion.
I assume L3115 was 268 when first painted yellow... There were a number of LZs painted plain orange during the changeover to QR ownership and it would be good to see them from somebody... (not 3120, of course since it has the wrong configuation for both manufacturers.)
The dates for the photos I have are mid-1980s, mostly 1985, but some 1991. Unfortunately they are not online therefore I can't share them, however there are a few images on Flickr that you could check.
Re 3107 yes I think you're right, it must be only 3108 (ex 260) that was missing lit-number-boards out of that batch.
I think the reason SRM did not do the early ATN versions was because they only lasted for approx 12-18 months (2000-2001). Personally I prefer the later ones because I wanted the named units.
Also, doing the later version meant that they only had to repaint them to get the PN and Interail units (albeit a couple of details that they chose not to add).
262 was as you say the first to be repainted in to ARG bumblebee colours but did not initially have lit-number-boards, but it did have the ditch-lights installed at that point. 268 and 260 also had ditchlights installed when first painted yellow, as you mentioned 3115 was still numbered 268 at the time, and kept that number for a little while after ARG ownership (roughly 2 years? something like that anyway).
There were as you say a few that were plain orange (and stayed plain orange I believe) after ARG became a 'QR company' and all of these had modifications too, ditch-lights if they didn't already have them, lit-number-boards and horns on the cab roof. These are 3109, 3114, 3119 & 3120.
3119 and 3120 have the same fitting above the cab-front windows as the early ARG rebuilds for the Darwin line (3101-4).
3120 of course was rebuilt from LW276 (Comalco R1002).
SRM could very easily do 3101 and 3103 in Aurizon/QRN banana colours in a second run as there are very few differences from the ARG version they are already doing. AFAIK 3104 was not repainted and the SRM version is as it was last in service. Fortunately for all of us it saw service in both WA and NSW in that condition.