Is it possible to trim clips with multiple video or audio channels?

Absolutely! If you use such a clip in Clip Trimmer, all available video and/or audio tracks are listed and you can choose which one to view/hear. Based on the video selection AirBox will play out the specified video track. The audio track selection is only for listening convenience while trimming - the audio tracks will be played out up to the extent of defined output audio channels (optional) and in the same order they are found in the original file, unless otherwise specified.