Contoller Spawner and transform problem in RViz

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I am building my own 4WD model and I am trying to implement 4 velocity controllers (one for each motor). The issue arises when I execute my launch file (which contains the controller_spawner node), the transforms between the base_link and the 4 wheels are non-existent. I have tried the joint_state_publisher node with the GUI (instead of the controller_spawner) and it works. However when I implement the controller_spawner node, the transforms disappear. I have made sure to download all necessary packages for ros_control. I have used the ros_control plugin in my URDF and even made sure the namespaces are all correct in the YAML, URDF and launch file. Every time I execute the launch file, I get the error: "Controller Spawner couldn't find the expected controller_manager ROS interface."

Then I get the error within Rviz that there are no transforms between the base_link and the wheels. When I run rospack list | grep control I get:

control_msgs /opt/ros/melodic/share/control_msgs
control_toolbox /opt/ros/melodic/share/control_toolbox
controller_interface /opt/ros/melodic/share/controller_interface
controller_manager /opt/ros/melodic/share/controller_manager
controller_manager_msgs /opt/ros/melodic/share/controller_manager_msgs
diff_drive_controller /opt/ros/melodic/share/diff_drive_controller
effort_controllers /opt/ros/melodic/share/effort_controllers
force_torque_sensor_controller /opt/ros/melodic/share/force_torque_sensor_controller
forward_command_controller /opt/ros/melodic/share/forward_command_controller
gazebo_ros_control /opt/ros/melodic/share/gazebo_ros_control
gripper_action_controller /opt/ros/melodic/share/gripper_action_controller
imu_sensor_controller /opt/ros/melodic/share/imu_sensor_controller
joint_state_controller /opt/ros/melodic/share/joint_state_controller
joint_trajectory_controller /opt/ros/melodic/share/joint_trajectory_controller
position_controllers /opt/ros/melodic/share/position_controllers
velocity_controllers /opt/ros/melodic/share/velocity_controllers

My launch file is:

<launch>

<!--Load the URDF file  --> 
<param name="robot_description" command="cat $(find monsterborg_description)/urdf/monsterborg.urdf"/>


<!-- Launch the robot_state_publisher to broadcast transforms to '/tf' --> 
<node name="robot_state_publisher" pkg="robot_state_publisher" type="robot_state_publisher" output="screen">
    <!-- remap from="/joint_states" to="/monsterborg/joint_states"/--> 
</node> 


<!-- Load the configuration of the joint controllers -->
<rosparam file='$(find monsterborg_description)/config/monsterborg_controllers.yaml' command='load'/>


<!-- Load the joint controllers -->
<node   name='controller_spawner' pkg='controller_manager' type='spawner' respawn='false' output='screen' ns='/monsterborg' 
        args='rf_wheel_velocity_controller rb_wheel_velocity_controller lf_wheel_velocity_controller lb_wheel_velocity_controller joint_state_controller'/>  


<!-- Loads the 'world' static frame -->
<node pkg='tf' type='static_transform_publisher' name='world_frame' args='0 0 0 0 0 0 /world /base_link 100'/> 


<!-- Open Rviz with specific configuration -->
<node name="rviz" pkg="rviz" type="rviz" args="-d $(find monsterborg_description)/rviz_config/monsterborg.rviz"/>

</launch>

My YAML:

monsterborg:

  joint_state_controller:
    type: joint_state_controller/JointStateController
    publish_rate: 50

  rf_wheel_velocity_controller:
    type: effort_controllers/JointVelocityController
    joint: base_to_rf_wheel
    pid: {p: 1.0, i: 1.0, d: 1.0}

  lf_wheel_velocity_controller:
    type: effort_controllers/JointVelocityController
    joint: base_to_lf_wheel
    pid: {p: 1.0, i: 1.0, d: 1.0}

  rb_wheel_velocity_controller:
    type: effort_controllers/JointVelocityController
    joint: base_to_rb_wheel
    pid: {p: 1.0, i: 1.0, d: 1.0}

  lb_wheel_velocity_controller:
    type: effort_controllers/JointVelocityController
    joint: base_to_lb_wheel
    pid: {p: 1.0, i: 1.0, d: 1.0}

Here is a small snippet of the URDF file for the base_link, one wheel and motor:

<robot name="monsterborg">

<link name="base_link">
    <visual>
        <origin xyz="0 0 0 ...