How to remove the top foot of inground pool wall?
A lot of people are doing the same thing here in the South- Western part of the States (mostly because of the drought). But it sounds like you have the plan (man). Be ready to deal with the embedded cage of re-bar. The hydraulic bobcat hammer is the apex demo tool to bust concrete, but you'll have to cut some tenacious 1/2 inch rebar (reciprocating saw, oxy-acetylene). I'm guessing you'll just let it drop to the pool bottom to act as fill?  The next tool you should consider using to cut through reinforced concrete is a concrete wet saw (like a Stihl TS400). This is a gas powered portable saw with a 14 inch blade and usually has a connection for a hose so as to spray the airborne dust from spreading. Also, be alert to the electric lines buried for any pool lights and expect to see 1 1/2 inch PVC encircling the entire pool shell. FYI: I've read (but never witnessed) an occurrence that may happen if the ground around the pool shell is thoroughly saturated and the pool is empty the pool can be pushed from the ground due to static water pressure.