This is one of those questions where we have no clear answer, since we're working from a sample of one. Was the IR a more or less unique case, or was it something which could plausibly have happened in a variety of regions if some broad conditions were met?
Exactly. And yet Technology Historians are one of the most dogmatically opinionated lot that I've met.

Far too politicised of a subject nowadays, so getting unbiased analysis is another difficulty.
Myself, I lean more toward the "unlikely, but possible" school of thought, ie that there were several places which could have led to an industrial revolution, where the details differed but it was still enough to allow a possible *IR. I'm open to being convinced otherwise, though.
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I haven't thought through this issue in detail, but Belgium springs to mind as the place next most likely to start an industrial revolution. Other less likely, but possible places include some parts of Germany and New England.
I'm of the same mind, and agree that some sort of IR is likely ITTL...but more and more I think it's heading off an entirely weird path unlike OTL's. You can accelerate some techs and retard others, giving TTL a real schizo-tech feel. Curious where electricity goes ITTL since it was a relative handful of seperate experimenters that drove it OTL and little in the electrical world is imediately intuitive or observable without specialized equipment. You might have a much more mechanical world. Conversely, an earlier Maxwell-type is also possible, pushing electronics/radio tech faster than OTL. If steam is getting held back ITTL then a weird world of Cavalry coordinated with radios? I think weapons tech advances as OTL, more or less.
I could really see the consequences of Auraurian crops and plagues shifting the center of population south from OTL. If Italy is suddenly a breadbasket thanks to perenial crops then perhaps there's a Second Renaissance. The OE could have a real resurgence here too and I think they would survive long enough for petroleum to make them a powerful, powerful economic and even industrial force ITTL.
Belgium is a great place for TTL's IR, having access to industrial resources, the example of Dutch economics and "windustry" (hmmm...earlier adoption of wind generators?), and an open discourse. Interestingly, the OE could be a player ITTL with it's boosted population. Could be the place where internal combustion starts up as oil is far more common than coal and I could see some Pasha investing in a non-coal engine design.
(moved by GK) Edit: One other important point is that some of the conditions for the industrial revolution (eg the British Agricultural Revolution) may happen earlier ITTL too. The Aururians have detailed knowledge of crop rotation and some other techniques which would boost agricultural productivity earlier, if that knowledge is applied. That may make up for the Aururian plagues, in fact, at least for Britain and the Low Countries (not so much for Germany).
Yes, the populations there and in the Med will boost sooner than Germany for the most part. Plus the Med has the Perenial Crops advantage, freeing up more manpower per capita! My only wonder is the Potato, which OTL made it rather quickly into Germany where its convinient ability not to be totally destroyed in the fires of war put it a step above cereals. I think either end of a London-Constatinople axis has potential, the middle not so much.
I'm inclined to think that steam engines will appear somewhere else first, and their applications will only be recognised slowly. Although the idea of an "Age of Steam" has a certain appeal.
I'll certainly decide this one way or the other before I start trying to depict the later future of this TL.
Fortunately, I still have some time to decide that - there's still a century or more of this TL's progress to depict first.
I have to admit, though, my gut instinct is to figure out an entirely different, but plausible, path to an industrial revolution. Whether that makes for a slower or quicker pace of technological progress will be a consequence of that path, not a prerequisite. I'll have to think about that, although any suggestions are welcome.
Very easy to bump steam a century either way. I mentioned steam appearing in the HRE. Pop up there and you could have it go unnoticed for a long time. Belgium is another possibility for a more OTL-like situ. Scandanavia, maybe (ph34r teh mytee Vasa steem zeplinz!

). Austria too (mines needing pumping, coal available), Bohemia in particular.
Without it wind and water power will go far longer. Curious if Aurauria has any potential there...watermills are certainly possible on the *Murray, but certainly not within the realm of the Gunagal. Their English "allies", however...
I mentioned wind generators, caveat being the unpredictable development of electricity and particularly electromagnetics (unpredictability^4). You can logically shift electrical fun as much as a century and a half or more either way.
Just for fun, here's a "Mixing board" of non-exclusive options. Just slide the "bar" in the center at "OTL" left or right for each option to suit:
Behind OTL ======||====== Ahead of OTL
Electricity (power)
Behind OTL ======||====== Ahead of OTL
Electromagnetics (radios & comms)
Behind OTL ======||====== Ahead of OTL
Electro-Chemical (batteries)
Behind OTL ======||====== Ahead of OTL
Metalurgy
Behind OTL ======||====== Ahead of OTL
Steam
Behind OTL ======||====== Ahead of OTL
Petroleum/Internal Combustion
Behind OTL ======||====== Ahead of OTL
Wind Power
Behind OTL ======||====== Ahead of OTL
Water Power
Behind OTL ======||====== Ahead of OTL
Locomotion/Engines/Drive Trains
Behind OTL ======||====== Ahead of OTL
Gearing/Mechanics (notably already well underway by PoD)
Behind OTL ======||====== Ahead of OTL
Air (Lighter-than)
Behind OTL ======||====== Ahead of OTL
Air (Heavier-than)
Behind OTL ======||====== Ahead of OTL
Chemistry/Material Science
Behind OTL ======||====== Ahead of OTL
Factory/Mass Production
Behind OTL ======||====== Ahead of OTL
Logic/Communications Theory
(Basis for Computers; tied to the punch card logic in looms, interestingly)
I think you have medicine, agriculture, and science boosted to the right already. IMO the science boost shows real hope for earlier electrical, metalurgy, chemistry/materials science, and possibly air, as a lot of scientific experimentation will be needed for those discoveries. Logic and Comms theroy OTL was highly tied to watermill looms and their punchcard system (sound familiar, CS Majors?), but doesn't have to be. Air beyond unpowered baloons/blimps will depend a lot on engine development, notably internal combustion, and electrical. Material Science and Metalurgy will affect the growth of other technologies.
If it were me, just for fun I'd go for a Schizo-tech world with delayed steam/engines but advanced electricity/EM where Hussars use hand radios to coordinate raids, Dutch wind-powered electrical grids (possibly with some battery storage) light up the factories for night shift, and saling frigates find their longitude by radioing back to Europe. But I'm weird like that.
