[DoubleF]

Infiniti - Nissan parts (Consider infiniti M series)
Lexus - Toyota parts (Consider GS or ES series. I don't know if IS is comfy for passengers)
Acura - Honda parts (Consider TSX or TL)

Audi - Volkswagen parts as Pylon mentioned

IDK what you mean by safety. All cars pass all sorts of safety gamuts before being allowed to be sold. Getting up a hill should be easy for any of those cars as long as the tires are in good condition. I think any vehicle (AWD included) may have issues with the hill if the tires are bald. I'd like to randomly mention, my old infiniti i30t had an overdrive button that when clicked allowed for more torque and higher rpms. The infiniti i35 was last produced 2004 so I'm guessing the M series is better for you to look at.

The above vehicles should have reasonable repair costs due to mass produced interchangeable parts from "another" manufacturer.

For instance:

I believe the M series infiniti shares many parts with the Nissan Maxima.
Lexus sharing parts with the Camry/Avalon etc.
and TSX and older TL (Not the new one post 2010) sharing parts with the Accord.