Hi Michael,
I would like to know the answers to the questions you are asking too, especially the most efficient ways to turn around a minor change[1]. Its taking a minute or three to turn around a change using the advice on the wiki[2], and if you are working on the as yet unreleased 6.0 there is some new documentation coming along[3]. My additional advice is to only mvn install the artifacts you know that have changed by using the -pl command line option. For example, this is my approximate compile line when I change one of my plugins for the ide. At the end of this I can refresh the browser and experiment with my changes.
time ( \
mvn install -pl :che-plugin-XXX-shared,:che-plugin-XXX-ide,:che-ide-full,:che-ide-gwt-app -Pfast \
&& mvn -f assembly clean install -Pfast \
&& docker run --privileged --rm -it -v /var/run/docker.sock:/var/run/docker.sock -v DATALOCATION:/data -v $PWD:/repo eclipse/che:nightly restart --fast \
) 2>&1 | ts
The time and ts is to add timing and timestamps to the whole process.
HTH,
Jonah