Yes, I would not clue Shop B in to what Shop A said. Just say, "it pulls to the right while driving in town under 30 MPH" or whatever the case may be.
As far as the knuckle goes, I find it hard to believe it needs replaced. The knuckle on these cars holds the wheel bearing, connects to the ball joint, strut, and tie rod end. It is made of cast or forged iron (I don't recall which) and is stronger than nearly any other suspension or frame component. The only way I could see it needing replaced is in some freak occurance. In other words, I'd get a second opinion, from Shop B.
As far as the stalling, I can understand your frustration as it is a safety issue, and it can be hard to duplicate. If it happens again I'd take very careful note of when / where. For instance, I currently have an issue on my Volvo where the trunk unlocks itself. It ONLY does it when the car is shut off. When I've caught it unlocking itself, it does it rapidly and repeatedly. Additionally, it seems to do it more often when it is humid out. Therefore, my primary conclusion is the pad underneath the trunk lid that you press to unlock the unit, has had the weatherstripping damaged, and moisture is entering the unit and making it think that someone is continually pressing on the pad to unlock it. May not be what's wrong but it gives me a place to start. The more info you have the better. Another example, that I posted somewhere on here recently, was with the fuse for the headlight circuit in an old Saturn and ex had, blowing randomly. Taking notes, it only happened turning one direction (right I think), with the lights on. I wasn't able to find the issue but took it to a good electrical shop and they finally discovered that it was a loose, live wire to some aftermarket fog lights that had been installed at one point. It would short against metal, but only on a right turn, as there wasn't anything to short against when the wire moved around on a left turn. ANYWAY, my point is, take note of how long the engine has run, how hot it is out, humidity (e.g. is it always when it just rained? Or dry but very humid?), etc. There will be a pattern at some point someone can use to diagnose and repair without just replacing components that might still be good.