I agree with you, when I was customizing my Vette I was both in love and overwhelmed with the options offered when customizing my 2017.
If you're not tracking the car at all, I don't suggest paying the extra cost for the Z07 package. I've had about 20+ lapping hours clocked in on my Vette and I still didn't go with the Z07 just for the sake of the cost to replace brakes, pads, rotors (down the road), etc.
As you said, to avoid buyer's remorse I would strongly suggest going with the 3LT, I found the difference to be well worth it. Its a premium car, might as well get the premium interior package.
Manual all day for me. Going to throw an MGW on it next year and put more lap time in.