Based on the OP's info, there's no reason for the Coolant reservoir to be "EMPTY" and---
It looks like the only thing the service mechanic is guilty of is not even noticing the lack-O-Fluid in that highly visable reservoir and it has nothing to do with the Auto tranny fluid line work --
Unless he removed it to get to the tranny fluid lines/fender liner, on the drivers side--
Maybe he dumped it and was gonna fill with new/improved MOPAR Fluid---and forgot-
This would warrant a return visit to the dealer and 24 question time !