The LS's I think have 17s, if anything it should be smoother riding than the others. We have the 20s on our '16 and had 18s on the '10. Both ride pretty similar, and quite smooth. Actually IIRC way back when one of the mags (C/D or MT) did a comparo with the Traverse, it didn't place particularly well against the competition but the ride was universally lauded.
Could be ride and road noise are a byproduct of the cheap tires the LS gets, perhaps replacing with something better quality might help.
The whine though, that shouldn't be. And the seats are hit or miss, they've never bothered me but I wouldn't call them the most comfortable things out there.
2016 SS Sedan
2001 Trans Am