ABS lights on I know that one of the wheel hubs and sensors were replaced

First watch when the ABS light turns on. If it stays on right after starting the engine, there is an electrical problem, and most commonly it's with a broken flexible cable going to a front wheel speed sensor. If the light doesn't turn on until after the vehicle starts moving, it is due to a missing signal from one of the sensors. A common cause of that is what it sounds like you already noticed. Rust builds up under the mounting ear on a front sensor. That increases the air gap between the sensor and the tone ring. The voltage pulses induced in the sensor are already going to be the lowest at low speeds, and with that increased air gap, the signal can get too low to be recognized by the computer. The fix is to pull the sensor out, clean off all the rust that has formed, and consider using a Dremel tool to remove a little of that mounting ear so the magnet part of the sensor sits deeper into the pocket. That will increase the signal strength and reduce false activation when coming to a stop.

It's real common to have noisy power steering pumps on GM front-wheel-drive cars but I haven't heard of that so much on the trucks. Obviously be sure the fluid level is correct first as air in the fluid will cause the pressure relief valve to hiss or chatter, but that same valve can cause noise on its own. The clue is it will have nothing to do with road speed as the tires will turn easier when they're rolling, but it is related to engine speed. You should be able to make the noise occur by raising engine speed while listening under the hood. Have a helper press the gas pedal. If you have the extremely dangerous "throttle-by-wire" system, moving the throttle at the throttle body will cause a mismatch between that throttle position sensor and the one on the gas pedal, and the computer may lock up to prevent the "Toyota runaway vehicle effect". That's not a concern if your truck still has the common sensor throttle cable.

Serpentine belt idler pulleys are noted for developing noisy bearings too but the sound is not really a buzzing noise. It's more of a crunching sound. The easiest way to find the source of the noise is with a stethoscope. They cost about ten bucks from any auto parts store.

The two should not be related. There are two things to consider, and I'm sorry to admit I'm not your expert on either one here. One is that many vehicles since the mid '90s have speed-sensitive power steering assist. As vehicle speed increases, power assist goes down to provide more road feel and better fuel mileage. More power assist is needed during low-speed maneuvers such as parallel parking. That puts added load on the engine. The Engine Computer is responsible for maintaining proper idle speed. If it's not responding to the increased load as the truck slows down, idle speed could drop too low leading to stalling.

There can also be an issue with any repairs that involve disconnecting the battery. On some vehicles the Engine Computer has to relearn when to be in control of idle speed and until it does, idle speed can be too low. On Chryslers, for example, the engine may not even start unless the gas pedal is held down a little and it won't give the nice "idle flare-up" to 1500 rpm when the engine is started until "minimum throttle" is relearned. That is done very easily by just driving at highway speed, then coasting for at least seven seconds. Until that is done, stalling at stop signs is a common complaint.

If you're having stalling problems while driving, that's a totally different symptom, and again, I'm not expert enough on your vehicle to address that. I can give you some pointers that pertain to older vehicles, but you might want to consider posting a new question so the other experts can see it.