from the sounds of it so far you have everything covered.. congrats on the new ride! Break in is definitely a good Idea and occasional spirited runs wont hurt it, you've had turbo cars before so I suspect you know what not to do.
My brakes tend to do the same but like yours only do it once or twice (2010 wrx) .. and only when its cold and I had it in the garage over night or very moist and car was outside overnight.
The oil change you can actually get away with doing it at the factory interval (3750mi for turbo engines) .. but sooner is never a bad Idea.
summer tires turn into bricks when its cold. The factory dunlops weren't terrible about this but traction is definitely reduced on dry and on wet they get a little scary, snow is a really bad Idea on summers. I live in southern VA and I have a second set of wheels/tires for winter. If you can swing it.. snag a set of steelies and decent winter tires. (tirerack.com has packages you can get already mounted/balanced) You have a car capable of great performance and safety, why sacrifice that for winter?
In regards to the electronics I wish I could help but my factory radio was the first thing I changed.. I also have a base model so no experience with the subaru navi. I'm sure someone will chime in though.