Can the Powered Up Remote (latest train version) pair with the Boost Move Hub?
Since June 2019, this is possible.  See here:
https://www.hispabrickmagazine.com/content/2019/06/03/powered-up-ii-powered-up-ii-networks/

Look right at the bottom of the article.


  The latest version of the Powered Up app (2.2.0) as well as the latest
  version of the Boost app include new firmware for the Boost hub. After
  this update it is possible to control the Boost hub with a remote
  control.
  
  Establishing the connection is a little more difficult than connecting
  a single Powered Up hub to a remote. It is not enough to just press
  the start button on each device and wait. You need to press the start
  button on both devices simultaneously after starting them to establish
  the connection (as if the Boost hub were a second hub in an existing
  network).
  
  Now you can control the internal motors (A and B in the Boost hub)
  with the remote control.