School busses are one of the perfect fits for electric engines:

Set schedule with down time to charge Specific route with known distances. Heavy and must drive up hills: which benefit from amazing torque generated by Electric engines. Large internal space for battery storage

Just pray Muskrat doesn’t somehow win the bid. We’ll never see them

7% at the end of a ~300mi roundtrip rural run is really cutting it close 😳 although if the journey is mostly flat I think it's OK, as long as there's enough range to go via any diversion if the road is blocked.

They could definitely get a bigger battery onto that roof, the main expense there probably would be customising the aircon to fit around a roof battery pack instead of buying one off the shelf

The electric buses here all have roof mounted batteries and they last pretty long - the chinese Yutongs are out all day with the heating on, but our domestic built ones seem to last only 3/4 of the day, and after that they vanish with the old diesel ones appearing on routes until the night

how many school routes are 480km?

Great, but I can guarantee most school boards can't afford it

"Rezoning." Have you seen local school boards?

Not sure about cooling, but there are a number of heating options that exist. We're basically looking at an RV, perhaps they could have some kind of diesel heater as a stop gap. I would think that could easily be retrofitted with something electric or ??? down the road. Mini wood stove haha. Maybe not kid friendly.