Startup apps not running at start up
In my case it appears that the problem was that some of these apps had been set to "restrict to launch" (in Settings -> Apps -> [each app]).  I don't know what this setting is intended to do, or why it was turned on. Also this does not seem to be a complete solution, but it appears to have ensured that some of them are now starting at startup.  

This setting appears to be unique to Lenovo phones, though I may be wrong about that.