The crack, the persistent southerlies and the warmth released by descending air(foehn winds and high pressure ridges) are enough to explain the thinning on the Greenland/CAA edge of the basin, though warm water seems to be affecting NE Greenland, EC shows 2C water in part of the crack there, right at NE tip of Greenland..
I had a bit of a look on Sentinel. I've attached a close up and wider view of ice in the Lincoln Sea, near the open water on its west shore, showing worn pebble shaped floes peppered with open water.
I also attached a couple of views centred on about 82.6,-102, about 100km NW of Axel Heiberg Island, also showing somewhat dispersed ice
Edit: The closeups are at Sentinels 500m resolution, I hadn't realised its screenshot tool left the scale out