A quick way for you to get the uff-input-blob-name and output-blob-names is that you can find them in the config file in deepstream.
For example, for detectnet_v2,
https://docs.nvidia.com/metropolis/TLT/tlt-user-guide/text/object_detection/detectnet_v2.html#deepstream-configuration-file
uff-input-blob-name=input_1
output-blob-names=output_cov/Sigmoid;output_bbox/BiasAdd