The throughput is the amount of HTTP data received by the Load Generator from the server. It includes the headers+body.
It's almost computed the same way for transactions,requests etc... The countdown starts when the first byte is received and stop when the last is received then the value is computed per second.
So for a transaction it will include all the data received for all the requests/pages inside the transaction from the first byte to the last one received.
In your example if each request had 1 Mb received during 1s each assuming they were executed sequentially so 2Mb will be received in 2s so still the throughput will be 1Mb/s. But be careful in graphs there's also the rendering graph that will aggregate the values per time interval.
NeoLoad does not provide throughput in Values tab so you can't get them.