On his Aerophile blog, Jacques Moulin has added the following:
Nota: Après diverses consultations cet appareil pourrait avoir été le SO 1014 (et non 1040) un dérivé du Bloch 1011, les ligne générale correspondent mais pourquoi le plan ne porte pas ce numéro(?)
So, as noted in SNCASO/Sud-Ouest Aviation (SO) designations, an inherited Bloch project but a MB 1011 derivative (MB 1014?) rather than the MB 1040 turret fighter.
Perhaps that also partly answers the powerplant question. If the MB 1010 MB 1011 were both to have close cowled radials (P&W R-1830 SIA-4G or Gnome-Rhône 14N-49 respectively), is there any compelling reason to assume that an 'MB 1014' or its SO derivative would move to an inline engine?