You obviously have no idea what it takes to engineer a new vehicle, especially one with newer technology like running off electricity only. It takes YEARS to develop and Disney wanted to get something out to compete with Lyft and Uber NOW. And Disney busses do not operate under the same conditions as city busses. They have to get up to higher speeds faster with less stops. GM isn’t going to spend hundreds of millions to produce a vehicle for Disney’s specialized needs with a quick turnaround time. Not to mention the challenges associated with electric vehicle technology, such as figuring out how to get the materials for the batteries without destroying the planet even more than gasoline production already does.
But they don't have to engineer a whole new vehicle, these vehicles are already readily available for commercial use, such as Taxis, shuttles, etc. GM has these vehicles available, that is my point, no engineering efforts are needed here. I know because I have seen them in use out here in California.
As for buses getting up to higher speeds with fewer stops, all the more reason to go all electric, seriously the electric buses can go from 0 to 60 in about half the time it takes a gas bus and apparently I was wrong about the range, they now have ones with a 250 mile range without any charging during the day and that is assuming 60% freeway speeds of 70 MPH. Here is one example of a bus (a couple years old now, so they probably have even better ranges available):
https://insideevs.com/byd-delivers-first-60-foot-electric-bus-in-us-featuring-275-miles-range/
And that is a 60 foot bus.
As for getting the resources they need for the batteries, that has already been figured out thanks to the likes of Nissan and others and there continues to be further improvements, we will soon see graphene batteries that basically take very little to nothing in terms of resources to produce, can charge at far more rapid rates and have little to no degradation over time.
Yes, in the beginning, it was more damaging, but much like has been mentioned, these were baby steps that had to be taken to get to where we are today, which have EVs being much greener than gas alternatives. Additionally, the used batteries will be recycled into other products, such as backup batteries for home solar systems, batteries for charging stations that will charge during off peak times and then use that electricity during peak times, etc. for about 50 to 75 years total life, including the 10 year/100,000 mile run in the vehicle itself, by which time we will definitely have better options for disposing of the batteries, this is with current technology, in another 5 to 10 years, we will be in an even better place.
This is actually one subject I do know a lot more about than you might think and I do know that Disney World could use EV buses, they have been tested quite well in a large variety of settings.
EVs currently are and will be going forward the cleanest transportation option, especially when powered by solar power. They are even cleaner than CNG or fuel cell vehicles, considering the amount of fossil fuels it takes to produce either CNG or Hydrogen for the fuel cells, these are far dirtier options than gasoline vehicles at present. Again though, this is being worked on and has the promise to be much cleaner in the long run, but nothing will be as clean as being able to run from pure solar energy, especially once graphene batteries make it mainstream and who knows, there may be an even better alternative to these batteries out there, but at present it works well.