Just a point on the broadcast you made regarding wpengine and their vagrant setup wpengine/hgv.
I used this extensively but towards mid 2016 sites I was developing on this were creating errors on live. I investigated further and noted that hgv was no longer being actively developed. I called them directly and although they wouldnt explicitly say they confirmed their focus was PHP7.0 now and not HHVM, and that hgv was no longer an active project.
I did say to them that they should state this on their GitHub page which is actively followed but they have declined to do so. As a result of their poor support, and lack of detail as to their server structure that you could replicate, we left WPEngine for this reason.