Grinding when braking & ABS light on a few days after tire rotation Please Help!

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I have a 2000 GMC Jimmy 4X4 Diamond Edition. After having transmission rebuilt (and an attempt to replace transfer case motor to get 4x4 working again since it hadn't been working for some time)....All seemed to go well with the transmission but the transfer case didn't solve the problem with the 4x4...they now think its the switch (actuator?) ...anyway...since they would have had to leave it in 4x4, they decided to remove the drive shaft so I would stay in 2 wheel drive instead. This made me very nervous but they said I wouldn't have any problems since it is only needed for 4x4....I was uncomfortable with this but didn't have much choice..They just said to try to bring back in when I can afford the nearly $100 for a used actuator switch and they could put the drive shaft back on and hopefully fix the 4x4. After picking it up from all of that, I noticed my steering wheel was a little crooked when driving straight, and it was pulling a little. (The trans shop claims that wheels were not removed to do the trans so shouldn't be related). I took it in to the place where I got new tires a few months ago to see if they could see if it needs an alignment and to rotate tires. They did the rotation but said an alignment wouldn't do much good since I need shocks. A couple days after the rotation, I noticed a grinding sound from my front brakes that doesn't seem to start until I am almost at a complete stop (not when I first start applying pressure to the brakes). I also noticed that my ABS light came on...(but doesn't appear to be staying on every time I drive). I read that they could have damaged my ABS sensor if they overtightened the lugs with a torque wrench with the rotation so I am about to take it back to be looked at but just wanted to be prepared. Is it likely that they caused this problem? I would think that if this was a brake problem, they would have told me I needed brakes when they did the rotation in the first place. Seems like too much of a coincidence that this just started. I shared about the transmission because I also want to know if it is normal to rebuild a trans without removing the tires because I also read that sometimes they only disconnect one side of something or other, which can put added stress on ball joints on the side that they didn't disconnect. Just want to be sure that what I was told is true, or if the wheels are usually removed to rebuild a trans. Sorry that was long, but this is really stressing me out and the last thing I need is more expensive repairs to pay for if they caused the problem. I would really like an expert opinion on what to do here. Thanks!