Hello Gary and Reuben Sir,
I kind of overviewed the source of zile and hopefully I have figured it out on how to add unicode support to zile.
I believe the following files in the zile library will get really few changes,the code is really well structured and not much of it will get affected to add support for UTF-8.
/zile/bind.lua
/zile/buffer.lua
/zile/completion.lua
/zile/file.lua
/zile/keycode.lua
/zile/search.lua
/zile/term_curses.lua
/zile/term_minibuf.lua
/zile/term_redisplay.lua
/zile/window.lua
/zmacs/specs/spec_helper.lua
/zz/eval.lua
There a few libraries that provide support for unicode.....slnunicode(available in the luarocks repository)......but I also found another one