Php 7 installed but 5.6 is active

EE uses php 7.0 as default script engine (when you create your site with --php7) but configures php 5.6 as a backup, in case the main backend dies for some reason.

That would explain why you get the unexpected php version on running site.

Try restarting services and checking again your phpinfo() just in case:

service php5.6-fpm restart
service php7.0-fpm restart
ee clean --all