There are several things here which I think we have some good news for:
need a rule that allows scene to stop at a specific point in time.
You have the “Pause Scene” action that can be used to stop the scene at any time. You can then use “Play Scene” to start it again, perhaps after some user interaction, or even “Jump To Scene Time” to move around in the timeline.
Once you have a time rule specifying seconds, and want to add anther time rule, you have to specify seconds again to make it work
When you create a timed event, the event is created at the current time on the timeline slider, Also, you can have multiple actions happen on the same time event by selecting the “Add Action” button.
No options on Cenario to start media on a specific time. I literally have to go to Audition and/or Premiere to cut my media and import it again.
Any media can be started at any time by using timed events on the timeline, or in response to any user interaction as well. Just use the “Play Media” action to play any MP3 audio or MP4 video. You can also use the “Stop Media” action to stop a currently running media item.
We are looking at implementing animation actions for objects as well so that you will be able to animate objects at any time, not just when making them visible.