146? Hmmmm
By, all I can say is that they must be desperate.
Mind you they won't be operating in 'rollback' territory, not much need for a water bomber above 260.
As for the APU (the one at the back - as quoted), they might as well remove it as the damn thing never was much good, neither was the Sundstrand that replaced it in the RJ).
Since they'd be likely to be coming back to the neares Forward Operating Base, they'll likely have a GPU so that wouldn't be a problem.
What I (although not an expert 'operator' I used to teach 146 Performance and Engines etc for BAe) would be concerned about is it's ability to get off the ground with a load as dense as the fire retardent, consistently with those 502s - what was it? 5670 lbs of thrust at ISA conditions and sea level?
We're looking at USA high summer temps and possible higher altitude FOBs as well.
Watch this space as they say . . .