Theoretically, yes, but we don’t encourage this because much of the value of OpenScholar comes from the nested parent-child nature of the sites, which schools will lose (especially on the global search element).
You do not have to get rid of your existing CMS. You can add OS incrementally, as many universities choose to do. Some start with only the new faculty sites. Others start with departments that are most in need of an upgrade. The beauty of OpenScholar is that the more that your university uses it, even via slow adoption, the more you will save on IT costs and the more your public facing sites will modernize.
Drupal multi-site is not a pre-configured, out-of-the-box solution for academia. It has many of the same underlying modules, but they have not been customized to meet the needs of universities. It cannot be used as a self-service solution for faculty and departments without a significant amount of on-site technical support and programming knowledge.
OpenScholar was designed, from the ground up, to address 99% of scholarly website use cases, WordPress was not. OpenScholar is an out-of-the box academic website builder. With WordPress, one needs to download and install numerous plug-ins (costly, and requiring development expertise) in order to replicate the functionality that is already built into OpenScholar. Once such customization takes place on a WordPress site, every edit requires further technical help and a support ticket be submitted. OpenScholar also comes with pre-designed themes that can quickly be customized with a school’s colors, logo and fonts, WordPress cannot do this as easily as we can. Customization is a necessity for universities that rely on WordPress and it is where all of the unforeseen costs of ownership stem from.
Yes you can continue to use WordPress; many schools that use OpenScholar also use WordPress. While OpenScholar does not integrate with WordPress by the strict definition of software integration, OpenScholar and WordPress peacefully co-exist on many campuses. OpenScholar, because it is a Drupal-based platform, can easily blend with any other existing CMS in that it is highly modular, will follow the same design standards set out by your Communications Office as WordPress and adhere to the same standards of Accessibility, Security and Responsiveness. OpenScholar is often used as another option for faculty and departments, in addition to WordPress. It is used, in some cases, for all new faculty websites and old faculty websites that need to be upgraded. The more a university uses OpenScholar, the more money they save on IT management and the more current the faculty and department sites look because they are easily self-managed/edited and updated by the site owners and therefore more easily refreshed with new content.