I'm not sure on if Softaculous supports it or not but I know hand-installed ones can. The only "gotcha" is to make sure the app supports Table Prefixes - most software should, but it ensures that every table that app uses is prefixed by something, such as wp_ for WordPress. This makes sure that if you have two softwares that use a table named "users," they actually have them named differently, like wp_users and forum_users. Since pretty much no two softwares have the exact same table formats, this ensures they can cooperate within the database.
Only other note though is that there is somewhat of a small risk of compromise; like hosting two sites from one account, one site being compromised could compromise the other. Since both softwares have access to the same database, it is theoretically possible for someone gaining database access to see the data in both softwares. I consider this a small risk though, as if someone's gotten that kind of access to the account, they're probably not focused in your database and have their eyes set on more malicious actions.
