SOLVED.
Upon my review I found that WHMCS was loading PHP extensions from an old legacy PHP 5.6 installation at '/opt/php56', in both '/home/visag391/public_html/php.ini' and directives added to the .htaccess file at /home/visag391/public_html/.htaccess. I also noticed that the PHP extension tidy was being loaded on the cPanel EA4 Installation of PHP 7.0, although the extension was missing. I've since reinstalled the extension and as a result I was to load http://visageweb.com.br/financeiro/admin/ without error. The steps performed are detailed in the following.
root@server01.visageweb.com.br [admin]# mv -iv /home/visag391/public_html/php.ini{,-$(date +%s)}'
`/home/visag391/public_html/php.ini' -> `/home/visag391/public_html/php.ini-1526518480
root@server01.visageweb.com.br [admin]# grep 'opt/php' /home/visag391/public_html/.htaccess
php_value include_path "".:/opt/php56/lib/php";"
root@server01.visageweb.com.br [admin]# sed -i-$(date +%s)} '24,92 s/^/#/' /home/visag391/public_html/.htaccess
root@server01.visageweb.com.br [admin]# yum -y reinstall ea-php70-php-tidy.x86_64