1) I'm the developer of mod_love.
2) I've some custom form elements (since ever) adding some custom groups/appareance...
3) I'm not a core developer neither a theme developer. Neither have interest on having those custom form elements anywhere out from my plugin.
4) I want to move the elements to use the new forms mustache templates
5) I cannot
Link to discussion @ Dev Chat: https://moodle.org/local/chatlogs/index.php?conversationid=23517#c657825