Interesting - just checked and don't see a way to disable the sound while maintaining popup alerts for these. Can't say anything about Bluetooth, but at least the calendar allows ringtone customization... Just get a dead-silent sound file and set that as your calendar alert tone.... May have to stick the file in /mnt/sdcard/media/audio/notifications/ringtones, and you may have to custom-create the last folder or two in that path, but once the folder is there, its contents will show in the "select ringtone" list (can be user to set full songs as ringtones, too, since it ignores the ~300kb ringer limit for anything in the folder).
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