I just want to clarify you have type C and then it couples with Type E? I want to use these for attaching tubing to the lid of the MLT. Do I need anything else (bulk head fitting)?
It will attach to any of the 'plug' styles.
What they have are both plug and socket in all three varieties: hosebarb, male threads and female threads. Any of the plugs will work with any of the sockets.
For your mlt, you could get a bulkhead, or you could just use a male and a female threaded connector. You would just drill a hole through your lid and connect the two pieces together. You might want a couple of washers to reinforce your hole, or not. It depends on the lid. http://www.gardeningcamp.com/thewiki/index.php/Hydro/PVCBulkhead
Granted, It's not as sexy as a bulkhead but much cheaper.
For my rig I bought stainless bulkheads from Pickles here on hbt. $12 plus shipping is a damn good price.