I once read a fascinating book that gave every B designation ever assigned, from the original B-1 (a canvas-winged biplane) up to the XB-70 Valkerie. Some of the B numbers were production models, some experimental, some varients of existing bombers, some proposed designs and a few of the later numbers were actually assigned to ballistic missiles.
Ferret was the name given to aircraft that used radar or other sophisticated electronic devices to “ferret out” targets and identify them in ways that other aircraft could bomb them.
They’re also called “motor gliders” - the engine is used for self-launching and, if required, return to base, but is shut off for soaring. On some, the engine even folds away into the fuselage to reduce drag.
Lockheed built B-17’s too. Ford actually made more B-24’s than Consolidated, at one point even cranking out 1 per hour at its Willow Run, MI plant.
Regarding the inclusion of the manufacturer in the model number, the USAAF did provide a code, but unlike the USN/USMC codes, it was a subcode that only showed up in the official paperwork that followed a plane, rather than being part of the actual model number.
As noted, above, when the Navy’s Chance-Vought F4U (Fighter 4th model U = Chance Vought) was bulit under license by Goodyear, it “became” an FG (Fighter (first model is assumed and not indicated) G = Goodyear) and the second fighter built by Goodyear was the F2G.
In the USAAC/USAAF, the manufacturer’s code was a two-character code at the end of the sequence. Thus P-47D-25-RE indicated a Pursuit aircraft, 47th airframe type, model D, variant 25, built by Republic while a P-47D-27-CU was Pursuit aircraft, 47th airframe type, model D, variant 27, built by Curtis. Short of having a plane’s paperwork in hand, the two models could have been indistinguishable and both would have simply been identified as P-47D.