Avoid all these other types except Solver (we call it Fixer at FB). Anyone who calls themselves these things is weird, and will be hard to rely on. Disregard levels. Disregard titles. Fix what needs to be fixed. Unit tests, CI, docs, there's no such thing as grunt work. Real leadership happens in the IDE and only code matters - everything else is overhead.
The tricky part is making all that code add up to something meaningful, though, right?
A thousand developers diligently and efficiently working away in their IDEs building completely the wrong thing is a terrible waste, and not something that can be solved by just having a staff+ ‘fixer’ come along behind and clean up.