Most forum software (among other scripts) supports "table prefixes," which are designed to allow multiple scripts to utilize the same MySQL database; on my local testing environment, I have WordPress, PHPBB3, MyBB, Joomla, and Drupal all using the same database with no issues. If you're installing through Softaculous and aren't able to set the table prefixes, then I'd recommend hand-installing the software - it also gives you more flexibility with regards to patches, as you don't have to wait for Softaculous to update to have the new version.