I see three distinct deep areas, in the locations you describe.
They don’t look particularly round/impact like to me. But a little tectonic squishing and an ice age or two could account for that.
This would be a good place for a PhD candiate to take some core samples!
According to the Firestone, et al. hypothesis, the impactors came in at a low angle from the north. This would have left the eliptical gouges shown in the lake. Also since this would have been an ice/snow ball comet rather than a rock or metal meteor, the crash signature is quite different. Shallower craters, less of a rim, not necessarily a slight mound in the center are their characteristics.
By all means read the book, it is fascinating, and the authors go into great and lucid detail on their scientific testing methods.