you can already can do “Add Video or Audio to the sequence at specific location“.
It may requires more than one call - but possible.
“GetAudioClip of a the clip in the timeline” → this would need to return an array as it can be added multiple times and on different tracks.
For your example, I think you can workaround this (albeit very inefficiently) by looping thru each items of every tracks and calling “getIsSelected()” on all items.