Here is a plugin that does all 3 actions : https://wordpress.org/plugins/merge-minify-refresh/
Plugin Description :
This plugin merges/concatenates Cascading Style Sheets & Javascript files into groups. It then minifies the generated files using Minify (for CSS) and Google Closure (for JS – fallback to Minify when not available). Minification is done via WP-Cron so that it doesn’t slow down the website. When JS or CSS changes files are re-processed. No need to empty cache!
Version 1.7.0 added the ability to generate .css.gz & .js.gz files. Your webserver may need to be configured to use these files. Here is how to use these files in Apache:
#Serve gzip compressed CSS files if they exist and the client accepts gzip.
RewriteCond %{HTTP:Accept-encoding} gzip
RewriteCond %{REQUEST_FILENAME}\.gz -s
RewriteRule ^(.*)\.css $1\.css\.gz [QSA]
#Serve gzip compressed JS files if they exist and the client accepts gzip.
RewriteCond %{HTTP:Accept-encoding} gzip
RewriteCond %{REQUEST_FILENAME}\.gz -s
RewriteRule ^(.*)\.js $1\.js\.gz [QSA]
#Serve correct content types, and prevent mod_deflate double gzip.
RewriteRule \.css\.gz$ - [T=text/css,E=no-gzip:1,E=is_gzip:1]
RewriteRule \.js\.gz$ - [T=text/javascript,E=no-gzip:1,E=is_gzip:1]
Header set Content-Encoding "gzip" env=is_gzip