1: Sorry my description was poor. The error only occurs on this device (of those I tried), and does not on the others I tried (which are all newer, and instead show the search bar beneath the rest of the buttons). This is despite the fact it’s running the same iOS version as a newer device I tried (10.0.1). The issue occurs both in Safari and Chrome (latest version). As far as I can tell, this problem relates specifically to the device: perhaps screen width? Both this device and Ed’s 5c are 640px.
8: All posts except questions posted on Meta have small avatar sizes. I think they are the same sizes as before, but this looks smaller since everything else got bigger. The one on this answer is an example — it’s tiny.
11: You think? StackOverflow does them to the left side and I think it looks good. It’s tight, but it’s neat and it works. I also prefer the alternative you mentioned over what’s there now.
12: Didn’t think of that haha.
And regarding the CSS... I agree with everything you mentioned, but for some reason I still feel like there’s a disconnect. It’s particularly the top bars, I think... they’re really blocky and quite unlike stuff you’d see elsewhere on this site, and on other forum/social software. Particularly on mobile: it makes you scroll a bunch every time you load a page, and the left-justified navigation buttons are odd to me. I feel like it could be simpler. Just a couple solid, narrow nav bars at the top, in the same vein as the main site header.
Getting really far into nitpicking territory now, so I’ll stop. Thanks for all the updates :)