Please Help identifying underhood components

I'm pretty sure "A" is not the VR but rather part of the smog system.
It does look more like this doesn't it.
upload_2021-12-29_13-6-24.png
Implemented '75 to keep the throttle cracked open on deceleration until the rpms drop below 1500.
Helps preserve the Cat.
https://www.mymopar.com/downloads/mtsc/326.pdf

As far as the vacuum amplifier or transducer, exactly what it is likely shows on the diagram in the engine bay.
upload_2021-12-29_13-15-44.png
Make a photo of that because its specific to your car and options.