Looking for guidance

I work for a company and have been tasked with creating an Adobe Premiere Pro plug which can create content that will be consumed by our custom training system.  Think of it like that old Dragon's Lair type game.  i.e. There are multiple clips, and transitions between clips are based on events that can be from an operator running the system, or automatic events, like from a device / sensor in the room.

We want the user to be able to create their own scenarios with Adobe Premiere + our custom plugin(s) that will need to...

1. Import multiple video clips.
2. The user would then use some type of roto-scoping to define regions in each clip.
3. Each region can be given attributes.  For example, the author could mark a region as "lethal", "non-lethal" on a person, or "glass" on a window.  I guess this would need to be a custom panel?
4. The user can use another custom panel to assign transitions between clips based on a preset list of events (like a drop-down list).  I think this would look similar to a visual scripting graph, where you have boxes representing clips, and lines between them that represent the event.  So for example, they would have clip1 and clip2, and they want to specify that when sensorX is triggered while clip1 is playing, the simulation should jump to clip2.  I think it would be very similar in functionality to the Blender Cycles rendering setup... just boxes with lines between then that "dock" to existing connectors on the edge of the box.
5. After everything is setup, the user would then export and the plugin would need to generate proprietary formatted files that our sim can read.

I have no experience with Adobe products or plugins.  My background is C++ (about 15 years ago), and more recently, C# / WPF.  I'm looking for direction / guidance in terms of what API(s) to use to accomplish this?  I see there are C/C++ APIs, as well as HTML/javascript.

Can anyone other there with experience writing plugins, and especially who have created custom panels with custom drawing on them give me some pointers and where I go for training, or examples that do a lot of custom panels with complicated drawing.  Possible some good books on plugin development?  Where do I start?  Prefer C/C++/C# approach, but if HTML/javascript is significantly better/easier, that might work as well.  Any drawing packages that would make it easier? etc.