Wavelab 10 video track

I have been waiting for this feature to be brought back into WL. Thank you PG.
If you have multi track audio embedded into the video file will WL 10 extract it when video is placed on a track?

If you have multi track audio embedded into the video file will WL 10 extract it when video is placed on a track?

Yes

This may be obvious, but I’m still uncertain after watching the videos and reading the What’s New page: I can edit the audio of a (multi-track) video and save it back to a video?

You can’t save a video from WaveLab. To merge the video and audio, you need another application.
However this is a feature which is planned.