I got all those same problems as you, other than that i don't have the click sound on the top of the device.
Problem in qwertys bottom part is so minor that i don't really notice it ever, but i have seen couple of guys where the "frame" was much more loose and i might have returned the device in that situation.

One problem that i'm a bit irritated too is the bottom part of the screen making click noise's. I have owned my N900 over 4 months and i think i already had this problem at some point, but the problem just disappeared at some point. Hoping it happens again.
Thought it's so still so minor that i woulnd't take the device back.