I would take whatever you can get. Used filter media helps with the cycle. But so should the 50lbs of live rock.
Try the pwc
and test, see where you are at. You have a ton of trates so one pwc
might not be enough to see a huge drop off.
Keep in mind that as your tank cycles it will also produce more nitrates. Keep your feeding to a minimum and don't add anything else til youre sure you finished your cycle.
With the lr
and sand you should probably see a small-ish spike of ammonia and nitrites, make sure you are testing so you will see it too. Then after that spike you should have a properly cycled tank. Yay!