There's a lot to unpack there. Watching some of the channels like VidIQ, Nick Nimmon, and Think Media may help... but I'll try to help as well.
The analytics pages need enough data [75-100 views] before they become useful, or populated by YT for that matter. It may also be time-based. You won't see much of anything until 2 or 3 days after a video publishes.
10% CTR is very good, and over time will drop as YT puts your video in front of more people.
Impressions count every time your video thumbnail is shown to someone, so external, internal, up next, suggested, subscription feed, they all count.
The search terms is part of the analytics pages for the video, and will be populated after a while, if you get enough views.
if your AVD is around 33%, then that's OK - most shoot for 50% [I do]. My videos usually get 35-50% AVD. If YT pushes it out to a wider audience, the CTR and AVD will plummet, since YT is trying it outside your normal audience - not everyone is gonna like your video or click on it, but that's OK. More what you're looking for is the retention graph, which shows dips and peaks - the peaks are good, valleys are where people clicked off or skipped around. Try to do that stuff less, I guess?
-John