I've published a map service connected as both the DBO & the data owner when trying to publish data. After publishing, the Version Management box is grayed out. Is there a step I'm missing?
You cannot use DBO in the SQL Server Geodatabase when working with Branch Versioning. The ArcSDE Geodatabase Repository must be owne by an user named "SDE", also the data cannot be loaded with the "SDE" user, you need to create a data owner user.
see my community.esri.com blog below.
Mapping and Charting Solutions (MCS) Enterprise Databases Best Practices
read the production mapping database guide books for SQL Server, and download my database template scripts for SQL Server, also read the database connection best practices.