That is the way it is designed.
Drag the audio to a lower track before moving the clip.
In previous version the audio followed the video, i think it was Pro2.0 and older.
Do not convert to dv avi or sd-mpeg for editing with CS4. If you system cannot handle mts have a look at Cineform NeoScene. https://www.cineform.com/neoscene/
There are other converters, but i find this one excellent.
No, unless you saved a copy of the project before adding the comps.
That is what i do: after closing up shop a Save A Copy to another drive. You never know…
Auto Save overwrites itself after so many times.
On the left of the track there are some icons. Hover over them till one of them shows : Show Keyframes. Click on this icon and set it to Show Clip Volume.