With SACD's, the case will provide all that you need to know. The logo standards are actually fairly clear and companies have been good about following them as far as I can tell. If it is multichannel it will say so explicitly. Without having the disc in hand, though, it can be tough.

The DVD-A disc sounds a bit odd. I'd try using the player's Audio button to switch between audio tracks, but if you can't get any digital audio output then it either doesn't have DD and DTS or the Pioneer is seeing a DVD-A track and ignoring the standard DVD-Video side (where the DD and DTS tracks live). Even then, a DVD-A track should be downmixed to stereo and output via optical/coaxial, so it is a bit curious.