I did 3 last year, I 600,600 and 500. One was really rusty, had to sawzall it apart. The other two I did with a razor knife and my impact. Just bust off the plastic caps for the supports, there's usually #3 phillips holding it together.
I did them alone, no real need for a hand, except if you can't cut the liner up small enough. Two took me 1 hour. The other one, substantially longer, but that was because of the yard set up. Pool down hill from driveway, about 200' away. Extra time was lugging it all back to the truck. I kinda didn't factor that in (DOH!)
None of them had a deck to remove, though I did secure it (one deck had sides and gates) for an extra charge.
None of them wanted the yard filled or seeded, just the crappy pool gone.
Personally, I think your bid is on the low side, but I don't know your resources, area, etc. Did you account for any footings for the deck aswell? Might be an extra cost.