In pursuing the JVC codes for the Emerald series TVs, I've found the following:

Most of the codes from code set 16 in the Remote Central database for JVC TVs will work with the Emerald series. HOWEVER, I also found that many MX-3000 remotes with operating system dates prior to May 20, 2005 will NOT output the codes, even though they appear to accept them. Later version controllers seem to be OK. (That explains why I made the remark about hit-or-miss learning activities in the original post.)