With what you've stated, you'll be best off with the bester/imanishi stones if you want to go with a soaker, shapton pros if you want to avoid soaking.

All of the stones you've listed will cut A2 and O1 without issue.

The sigmas that LV has are geared toward high speed steels, and it appears from all write-ups about them that they take care of high speed steel with efficiency maybe similar to diamonds, but they are soft stones and the speed difference on high carbon steel will not be nearly as much - not enough to warrant the extra flattening they'll require.

I have used (own or owned, actually) bester, naniwa super stones and shaptons, and all of them cut everything you've listed with ease. I can't comment on the imanishi stones unless they are like the besters. Besters are porous, thirsty (but soak quickly), fast cutting and stay flat for a long time. For practical use, I still like the shapton *pros* the best (not that excited about glasstones). No soaking, meaning if you're in the shop for a half hour, you need no forethought to use any of them - you just go to them, spritz the surface and sharpen. They cut A2 and high carbon steel as fast or nearly as fast as anything, leave a very uniform scratch pattern at the edge, require little flattening, and are ready to use as fast as you can squirt a mist on them. They also obliterate any traditional japanese tool steels (the white, blue and boutique blue steels).

There are US and japan market stones. I have some of both. I can't tell a difference. There is a huge difference in price, though.

*I think* Shapton says that the 12k is a 1.2 micron stone and the 15k pro is 0.98 micron. You will not be able to tell a difference in use if there is one, and the 12k stone can be had for as little as $85 shipped if you look around (ebay, etc) and get it from japan. If you use microbevels or hollow grinds, the 1k and 12k are all you would ever need, and if you want to go finer than that (I don't know why you would for woodworking), you could go straight to LV green stuff on MDF. I am not aware of an artificial stone that will create an edge superior to the green stuff on mdf, and I have used the shapton 30k stone (which I think is generally a waste of money unless you're in a contest with someone).

There's nothing wrong with soaker stones unless you like to work like I like to work (I may have an hour here or there to work sometimes, and I have no interest in soaking stones or dealing with grit contamination on my fine stones or putting them in separate containers to avoid that. I like sharpening to be a sub-minute activity).

The shaptons are very hard and non-porous and do a good job of allowing you to work in both directions if you work freehand - without much concern of gouging the stones. They have some stiction and are a little more dense on the surface than a soaker, but technique overcomes that easily. You can sharpen a hollow ground chisel extremely quickly on them by working the chisel in a side sharpening pattern through the fine stone and then taking a few short strokes with the finest stone to get the scratches perpendicular. I would say from the time I arrive at the stones to the time I walk away with a hollow ground chisel that starts fairly dull, it's probably 30 seconds to hit the bevel 1k and then 15k, and lap the back about 10 strokes.

The only other way to match that kind of speed is to use diamonds, and I'm convinced the edge isn't as fine with them in a two step process, and the scratches aren't nearly as uniform.

The naniwa superstones are a lot the same, but they don't cut quite as aggressively and are a lot smoother to use - the feel of them is almost like a medium hardness natural stone (i understand naniwa worked to get that feel on purpose). The shaptons will cut HSS with some skill (they will make it sharp, they will not hog it like diamonds, but they will make it sharp just fine with microbevels or a hollow grind - you don't want to have HSS without the ability to power grind, anyway), but I hear the superstones won't do it so well. I never tried the one I had on HSS.