Before getting to into the details of your issue, it is important to understand that ONNX and TFLite can describe many operations that cannot run on the Hailo accelerator. These types of operations are often at the beginning and end of a network and need to be removed for the conversion process and then reimplemented on the host CPU.
For the start_node_name and end_node_names you need to select the first and last layers that can run on the Hailo device. These are not necessarily the first and last node in your ONNX. You can us a tool like Netron to review your ONNX file.
For your network I recommend you first review the conversion of the Yolov8m Pose model that is part of the Model Zoo. You can find the end_node_names for that network in the YAML file.