Use an angle grinder with a cut off wheel on it to cut the siding. A skilsaw with the blade turned around gets dull fast and starts throwing teeth.
I just cut aroundthis whole building. Where the stone face starts and those big windows are new also.
What I use, is a handplane blade. Its thinner than a prybar, has a sharp point and is long enough and stiff enough (no homo) to pry trim off and wont damage the wall.
I bpught a USA made Milwaukee circ saw last sunday at a flea market for $20. Put a new diablo blade on it and it works awesome.
I used it all last week framing at work
I would have to say that a good chunk of the higher quote you g o t would be rising prices of materials,especially lumber.
You cant use prices from a year ago, **** gets alit more expensive over a years time.
Btw, just reading what you wrote, I'd probly pad the estimate with a "********...