Only my sedans get online bookings and my minibuses never receive online bookings, why is this?

This can be solved by creating manual vehicle classes, for example:

• Deactivate standard and large vehicle classes
• Add vehicle class “Any Type” and set “passenger” 1-4 and add both sedan and minibuses
• Add vehicle class “Any Type,” and set “passenger” up to allowed maximum seat capacity and add minibus only
• Enable these 2 new classes under “booking options.”

Another option to keep it clear is to create a class with the vehicle type as the name, e.g. sedan class / minibus class (but passengers will expect a sedan vehicle type to be booked if they select this option.) With this option, you will need to set as well the correct vehicle capacity so sedans can take the required number of passengers for minibuses.