GPS no workie on 911
The 911 system in the US ins *unable* to use the GPS data from phones. This is not a carrier issue, it is an infrastructure (of the 911 system) issue.
The best the carriers can do as a result is give an appx location based on cell location.
As to the ghost calls issue, IDK if that is a T-Mobile or Dallas infrastructure issue. 911 calls do not go over the normal cell routes, they have a priority circuit (of sorts) so that if you have a phone with no SIM, or expired SIM, or revoked IEMI the emergency call can still be placed. If the issue is with how T-mobile handles this priority circuit and that's what caused the ghost calls then yeah, they may have liability here, if it's the city's link that didn't act to spec then...