Let's Encrypt is a non-profit organisation that provides free SSL/TLS certificates. They are currently in Open Beta and you can get a free certificate starting today.
Symfony is a popular tool for content management system builders. Here is a short list of some tools that use it to build a CMS.
The latest iterations of PHP in the 7.x branch are great improvement over the last PHP 5 version, which is 5.6. However many applications don't support it and it will be useful to run many versions on a local environment. In my case a laptop running macOS (OS X) and using the Homebrew packet manager. This is how to run both PHP 5.6 and PHP 7.1 simultaneously.