Are your Arkansas stones cut for the EP or are they bench stones?
Oil, water, or dry. I've read much conflicting advice on this one.
Oil floats the swarf more effectively. Swarf gets pushed off the stones more easily so your knives are less likely to scratch; as long as the stones are fairly clean. Further, the stones will take longer to clog. There are a few downsides to oil, though. Oil sharpens slower, oil doesn't sharpen as fine (don't know why) and once they're dirty oiled stones are a bear to clean.
Dry stones sharpen faster and finer -- that usually makes for better edges. Dry stones are much easier to clean.
Water and soapy water fall in the middle.
When I use oil stones, I usually -- but not always -- sharpen dry.
If I use water can I switch to oil next time?
You can switch back and forth from oil to dry, no problem. It's easy to get the oil of an Arkansas stone by either running them through the dishwasher (which you can do as part of the regular wash); boiling them in a pot with some ordinary dishwashing detergent; or soaking them in mineral spirits then thoroughly rinsing and/or soaking them in plain water.
I've read that if I use oil once I'm stuck with it. True?
Technique, I learned to sharpen mostly from Jon at JKI's videos, and all the videos I've seen for Arkansas type stones use a sweeping motion rather than the push pull method that the Japanese seem to favor.. Can I use the more Japanese method that I know, or do I really need to do the one motion heel to tip sweep type action.
You can use whichever motion/action you like.
FWIW, "push pull" is not particularly Japanese, nor is "heel to tip" particularly western.
I never got the India stones but I am leading up to the soft Ark using my stock edge pro stones (I believe they are aluminum oxide). How high should I go on the edge pro before switching to the soft Ark? I'm guessing the 220 or 320 should be good.
"India" is Norton's trade name for their synthetic aluminum oxide bench stones. There's nothing which makes India better or worse than other AlO stones other than that they're very good quality for the price. FWIW, there are a few better synthetic oil stones on the market which are better than Indias, and a ton which are worse.
In the greater scheme of things, Arkansas stones are slow compared to good synthetics. I prefer to start the first burr with a fine India, and switch to my soft Ark simply as a time saver. I prefer to use a soft Ark as a lead in to the black as opposed to jumping to it from the fine Inida because it gives me a sharper and more durable edge.
I'm not sure why the black likes the soft Arkansas so much more than a fine India, but it does. As a rule, I don't usually favor tiny steps between stone grit levels, and as the fine India and soft Ark are both "medium/coarse" stones -- too slow to move enough metal for profiling or repair, too coarse for a finished edge, but perfectly suited to polish out the scratch left by the first stone and pull a burr -- the combination seems especially redundant. However, experience tells me that using a soft Ark is the right way to get the best finish from a black or translucent Ark, and that its faster to start with a lead in to the soft Arkansas. So much for theory.
As to which particular EP stone would best precede your soft Ark, I can't really say. Once you've had some experience with the stones you may not even need or want a synthetic AlO lead in. Also, the EP grit numbers are very idiosyncratic and I can't decipher them for you. You can shoot Ben Dale (Mr. Edge Pro) an email and ask him which stone is most like a fine India, but you'll learn more by trying the various permutations yourself.