...Apropos, there is an aviation analogy that might be thrown in for sheer levity. Even an aircraft propelled with advanced engines such as turbojets, turbofans or ramjets can still feature a small propeller or two. These are run on reverse, making use of "ram air" (that is, the flow of air past the plane due to the plane's own motion) to run a generator to create electric power or hydraulic pressure.
Rotating gadgetry located in front of the warp engines could thus be something of an "identification by association" thing, a way to suck parasitic power out of the ship's primary means of motion. Not actual motion, of course, but the subspace flux or whatever at the "sink" end of the warp coil set. Perhaps the rotors rotate as space itself flows in - and can wholly incidentally also be "autorotated" for moving more physical things such as gases in and out if the need arises?
Not as good a match for the Bussard ramscoop terminology as #1 or #4, but perhaps workable, as "ram" and "scooping" are featured. In a manner completely unrelated to Robert Bussard's brainchild, unlike with #1 and #4, but perhaps the Trek gadget is named after Felicity Bussard instead?