[Washington]

I can't comment your points #1 and 2, as only a developer could, and good luck at getting an answer from Apple (OK, I'll withdraw that - please stay quiet Sascha, let's not start again), but as to the solo and mute function being implemented in several different location, it's a great function. Here's the thing:

By default, the S and M buttons are the same whether in the arrange window or the mixer. But in the settings (or preference, don't remember) tab, you can set the ones on the mixer to behave as the standard mute and solo functions you'd have on a desk, while the ones in the arrange window would then apply to your "virtual multitrack recorder". I'ts particularly useful.

One example: you have gate on a rthm gtr track, triggered by the snare. If you mute the snare from the mixer, you won't hear it anymore but the sidechain input would still be fed from the snare track. If you mute the snare "recorder output" (that is, from the arrange window), your snare track is entirely disabled.

By the way... it's in the manual. HTH