I can't think of a reason for the speaker to cause issue with the sensors. Were all of the sensors placed back into their original locations? I would not think it matters, but if they are capable of being calibrated, maybe they are sensitive to location.
The images of the ADD bumper, in their...
Yup.
Might want to check for any damage to the connections and/or wires to these sensor locations. Is there paint on the LH/RH blind spot sensors at the corner of the bumper?
The only way I am familiar with is to go into the meter display edit using the left side steering wheel buttons. Once you scroll to trip A or B you can hold the OK button to reset them.
I have the 41.22 hitch slider installed on my Taco. Since it doubles as a recovery point it still protrudes from the hitch face about 2.5 inches but then wraps around the bottom of the hitch.
The "puck" looking piece in your photos is actually a speaker. There is a matching one in the front. They're used for the high pitch tone output during movement under hybrid power.