For #7 we can learn VJET way (http://eclipse.org/vjet/download/)

VJET has some support for Node.js, though it seems to be old (for 0.4 version).

VJET ANVIL (former name JavaScript Type Libraries) like TypeScript #24 (but not like NJSDoc #16 ) is using precompiled libraries to get type information.

I cloned sources to https://github.com/Nodeclipse/org.eclipse.vjet.typelibs , as
https://github.com/eclipse has only 4 repos mirrored from Eclipse