[vlfig]

Author here. Thanks for reading.

> * What build toolchains are suited to these arbitrary DAG arrangements?

In general any CI/CD tool that allows for easy composition of jobs/pipelines, where versioned artifacts are a first-class citizen and can be the outputs and the inputs of jobs. Preferably one where the graph is emergent, i.e. just a consequence of declaring which "jobs" (taken loosely) depend on which artifacts.

I've had good experiences with GoCD https://gocd.org and Concourse https://concourse-ci.org, the latter being a fresher, younger take on these concepts. I haven't surveyed the landscape recently so there may be other tools that work well.