I installed the “Network Subsite User Registration” plugin which gives an extra menu point at each dashboard under Users>Registration>allowed There is, however, a glitch as wp-activate.php redirects to the main site in “signup-welcome” and “lead-in” sections that need to be commented out.
After all, I changed to “Profile Builder“, but it had its own problems, missing functions, large overhead, $$$ for extras and strange formatting instead of using the theme definitions.
Finally, I ended up with https://userswp.io , a lightweight user profile plugin that features front end user directory, a registration and a login form. The only modification here is another line in my child theme to suppress the WordPress admin bar.
#wpadminbar { display:none !important;}