The “XML Parsing Error: not well-formed” are due to xml templates which are loaded via requirejs. You can safely ignore them.
This is my workflow:
- Add mockup to source checkouts,
- Send the resource registry in development mode,
- Send the bundle I want to work on / where the mockup pattern is loaded in into "Develop Javascript"
Then you just have to reload the page and see all changes immediately.
When I want to re-create the bundle I use ./bin/plone-compile-resources -b BUNDLENAME (See more options by passing --help). You need somethins similar like that in buildout: https://github.com/plone/buildout.coredev/blob/59f8791d1419d23833316a694d134762a955cc4a/core.cfg#L56
Of course, the things in mockup's dev docs also apply. Especially the tests should pass.
I do not create any bundles via the grunt setup in mockup anymore.