Hi Samuel,
I think you have a sound approach as to differ between implicit knowledge and explicit knowledge - and automate the last bit. I have used Wardley maps to derive a similar test strategy. You can read this great piece about using Wardley maps and cynefin to identify your system under test:
There are at least two challenges with the approach. How does your in-house testers deal with not testing everything? … as they might have been previously, I explore this in my post: How Automation Affects the Business
Secondly consider to include the automation team in the “in-side” work flow. make them a part of your team, as to avoid the “over the wall” issues. Especially if in another time zone.
There might be more ideas for your i this thread: