I switched off the on-screen display on the BD-01U, but I still see icons on the screen. How do I defeat those?
There are two settings for the on-screen display. Turning off the On-Screen Display switches off the "info bar" at the bottom of the screen. To disable the play, pause, etc. icons, switch off "On-Screen Guide" in the Playback menu.
Is it possible to get Dolby Digital 7.1 audio from the optical or coaxial output?
No, Dolby TrueHD and Dolby Digital Plus formats are only output through the HDMI output. The optical and coaxial outputs are limited to Dolby Digital, which has a maximum channel count of 5.1 channels.