Update question: Steering Wheel Controls 2005-2006 SR5 4x4

This is a followup post with questions based on the excellent thread that details adding steering wheel controls to a 2008 Tacoma.

https://www.tacomaworld.com/threads/installed-steering-wheel-audio-controls-on-my-08.316944/

I have a 2006 SR5 4x4 Access Cab with the OEM JBL sound system and no steering wheel controls. I recently added a Bluetooth integration module USA SPEC BT45-TOY which works quite well. I would like to add left hand steering wheel controls for volume, track/tuning, and mode. I prefer the stock head unit because I frequently drive in places where a more elaborate head unit will simply attract unwanted attention.

My questions are as follows:

Is the factory Toyota/JBL head unit that had the option for integrated CD changer compatible with the left side steering wheel controls that were also an option on 05-06 models?

IF SO:

My USA SPEC BT45-TOY Bluetooth module is programmed to answer/end calls using the track selection buttons on the head unit. I would imagine that this function transfers to the up/down button on the steering wheel controls. Is that correct?

From what I gather from the original post referenced above I will need a new airbag, airbag cover, steering wheel controls, and spiral cable. Are there any other parts that would be necessary for the 05-06 mod?

I also see that used steering wheels can be obtained in good condition that match the appearance of my stock steering wheel and that already have left side controls installed through at least 2009 models. Would those function as a direct replacement for earlier models? If so, through what model year?

I am assuming that the right side phone controls that are available are pointless with the 05-06 JBL head units as well as with my Bluetooth integration module. Please correct me if I am wrong.

Thanks in advance and I would appreciate any other suggestions if I have missed anything.