The correct powered wiring harness for your 1985 Peugeot 505 sedan is the Curt Powered Wiring Harness, # C59496. This is basically the same wiring harness as the # C56175 that you referenced except it has the additional power lead for the vehicle battery.
The # C59496 is the harness that I would recommend for your vehicle. Using a powered converter box will keep the additional power draw off of your vehicles tail light circuits and will provide more power for trailer lights. This kit... view full answer...
For your 2009 Peugeot 407 we have roof rack fits, but none from Yakima. The Rhino Rack part # RRVA118B-2 and # RRSX100 is listed as a fit and would work well.
I attached an install video that shows how the rack would install on a similar vehicle. view full answer...