Chris
All the early Lockheed twins had double control, including the Super Electra and Hudson.
I don't think the second control was discarded, but the seating facilities was very much reduced. I have never been inside one so I don't know exactly what it looked like, but if you have Air International Nov 1985 on page 244-45 there is a cutaway drawing which shows what it looked like. Judging from that drawing the arrangement must have been very uncomfortable for anyone trying to pilot anything from that position. So I would say that Eric Brown was both right and wrong in his remembrance. The reason for the arrangement was of course with the Hudson you needed access to the nose.
Possibly (I don't know that), you could rather easily take out the second controls/seating altogether, but, if so, the drawing does not depict that.
With regard to your essential question, I have no answer since I don't know the training criteria in Coastal Command. Logic (and my survival instincts) would say yes, the Navigator had hopefully at least some flying experience. He would at least be the logical choice, since he (again hopefully
) knew where they were and would also know where they should be going.
Cheers
Stig