@George Kaye did you mean to post your response on another thread?
Getting back on-topic... Today I received a marketing message from Roland in my personal email advertising additional styles for the FP-E50.  When I clicked the embedded link, it took me to a Roland Cloud page.  There, I learned that the FP-E50 seems to have style compatibility with legacy Roland arrangers!  This supports my earlier conjecture that it has "real" Roland Operating System DNA.  I also wasn't surprised to learn that the downloadable styles for the E-X50 and E-X30 are NOT compatible with other Roland arrangers (probably because they borrow from an entry-level Yamaha OS.)
So in the FP-E50 we have the first new "real" Roland arranger product since 2015.  What will Roland Japan do for an encore?