Regarding the similarity of the Scorpene and Shortfin designs it is significant what Sean Costello (CEO DCNS Australia) stated in ASPI's The Strategist on 8 April 2016. He wrote:
"The main area where Barracuda design references were not used was in the area of the electrical system (batteries and voltage), power generation (induction and diesel generators) and propulsion (main electric motor). In these systems the design reference comes from the Scorpene class of diesel electric submarines, or from an existing submarine technology within DCNS. Existing technologies are re-used in all systems in the Shortfin Barracuda Block 1A. System by system, the whole ship performance is validated and the design loop closed."
If the now known Scorpene characteristics can be related by computer modelling (or directly by Costello of DCNS) to the Shortfin this does not bode well for the Shortfin's future stealth. Computer modelling, which is constantly used by commercial and strategic competitors (think submarine design bureaus in China and Russia) can heavily compensate for the size difference between Scorpenes and Shortfins.
Also the later Scorpene models (for India and Brazil) were designed over the same period (2000-2010) as the DCNS Barracudas (from which the Shortfin derives).
Major similarities between the Scorpene and the Shortfin will be in hull shape and pressure hull steel - which together influence acoustic and magnetic signatures that an enemy looks for.
BTW - The document leak might also give Pakistan’s competitors insights into Pakistan’s five DCNS Agosta class completed 1979-2006. The Agostas completion overlapped with the first two Scorpenes completed for Chile in 2005 and 2006. Scorpenes and Agostas also share portions of the French SUBTICS combat system (see my details on SUBTICS for Scorpenes and Agostas here).