french bikes often have weird threaded bb shells, and you may want to forget about changing cranks until those break... then again motobecanes may have used english threading, i'm not really sure.

honestly i don't think that bike is worth buying wheels for, and brakes, and the whole nine yards.

just disassemble, clean, polish, regrease, repack bearings, and maybe get some new brake housing and cables. if you end up having to buy new wheels you may need new brake calipers and it just all gets very dumb very quickly. BD bikes can be awesome and they can be crap, but even new crap is better than old crap you've spent 200 dollars on just to get it to work.