Sorry for the late response - but earlier this week Björn Grüning and I added various support to Galaxy's development branch for Singularity.
The following pull request added Singularity support in job running (https://github.com/galaxyproject/galaxy/pull/4175
) - here job destinations may describe the paths to Singularity containers. It may also work with Singularity 2.3 to just specify Docker containers and let it auto-convert - I haven't tested that.
For "best practice" tools - these are tools that have only requirements that can resolve via Conda in the best practice Conda channels we can do even more - we can build Singularity containers and use them automatically - either ahead of time or build on the demand during job execution.