According to Federal Tax Day, a number of speakers, including those from AICPA and Council for Electronic Revenue Communication Advancement (CERCA), at the Oct 16 public hearing for the proposed regulations have asked the IRS to provide clear guidelines on when Sch E activities would rise to the level of a §162 trade or business.  The rationale is that this should avoid taxpayers applying different interpretations and simplify tax administration.

It is also reported that the "regulations are expected to be finalized before the 2019 tax filing season."

In other words, the short answer is dunno yet but watch out for further development.