To bring this to a close, I had Shop #2 do the service last week and have checked the car after short and longer drives - no leaks. And Shop #1 came through with payment for the work.

I talked to the tech at Shop #2 who did the work and asked if he checked the mechatronics sleeve. He had and said it showed no signs of leaking.

I guess the moral to all this is that tightening the bolts holding the pan to the casing must be done per ZF's spec, or suffer the consequences. I'll never know what went wrong with Shop #1 - wrong tightening pattern, over-torque, under-torque - but am happy my garage floor is not collecting more transmission fluid.

Thanks all for their advice.