Question before upgrade, about php version

Hello, I realize that at some point i need to upgrade to Easyapache4. I use Wordpress and php5.5 and today noticed a plugin i need requires 5.6. I run WP on one site (which i suppose supports php7) but i also run a php store that will not work with 7 and never will. Will i be able to upgrade to Easy4 and run WP with php7 and another site with 5.6 (or 5.5 as now). Also will upgrading to MariaDb break anything in wordpress? thanks /J