There is no need to stop “plugin enumeration”, just use plugins from a good home and make sure you have restrictive file permission setting on your server.
In theory you can use htaccess to mask the original location of the plugin on the disk and write some code to serve any JS and CSS file as if they are located at some other directory, but this depends on the way the plugin works, some plugins might work while some might fail.
But in the end if a plugin gives admin credentials to everyone that surfs to example.com/?admin=me then the bad guys don’t even need to enumerate the plugins on your site, they will just go directly to that url.