A conversion should not automatically remove non-Oracle RPMs but we should inform a user of the systems state.
As seen in #2 a user may have RPMs from CentOS and OracleLinux installed and the system operate normally.
In the real world it's natural for a system to hold RPMs from different vendors, for transparency we should inform the sysadmin what they are to highlight any bugs/edge cases in this tool.
This issue should not be addressed until after #2 to avoid information overload