Serpentine belt/tensioner issue

Upon start up on occasion, my car's steering is difficult. After the first little turn out of my parking spot, the steering is fine going down the road. No issues whatsoever even after other startups. It seems the temp dial on my heating/ac accessory is difficult to turn too at the same time the steering is difficult, but also becomes fine down the road. Also, during cold weather, something around the front of the engine squeals for the first few miles and stops squealing. It doesn't squeal at all during the warmer months. A gearhead friend of mine said the serpentine belt looks really good and has a lot of life left. Could a bad tensioner cause all these symptoms?

I took it to the dealer and they "recommend" replacing the alternator and A/C compressor belt(s). I don't trust either dealer near me because they've both been caught trying to do unnecessary work to fix problems.