1) In my experience so far, not sure if it differentiates (I think it probably can since it can identify freestyle), but it did not display a secondary stroke for me. I swam predominantly free (44/50 laps) and did not see breast show up anywhere.
2) can't speak much to the accuracy of heart rate data as I didn't confirm manually by taking pulse to see how close it was and this is my first HR monitoring wearable.
3) correct, didn't need the iphone nearby for this to work. just toggle to the workout menu, select pool workout, set goals (optional), and start workout. it did take me a little while to figure out that you need to swipe left to get to the menu to end the workout. also, I think if you double tap or hard press it creates a segment/interval (though I'd really like for it to auto-detect when you are resting).
In regards to the level of detail displayed/stored from the AW2, I'm hoping that apple builds and expands this as it is lacking relative to other options out there. I'm also hoping that the swim.com app gets approved soon so I can give that a run. In case you haven't seen it, here is the type of data that it captured swimming with a pebble time.
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