Wirelessly posted (BlackBerry: BlackBerry8530/5.0.0.1030 Profile/MIDP-2.1 Configuration/CLDC-1.1 VendorID/417)
Avios.
AA considers Easter Island to be in the South Pacific, so you would either have to go via PPT if you want to redeem a single award (assuming that there is a published through-fare from DTW/ORD to IPC via PPT), or redeem for two awards (North America to South America 1 (for LIM) or 2 (for SCL), and then a second award from South America 1 or 2 to the South Pacific.
All BA awards are priced by segment and distance flown on each segment; BA no longer uses a zone system.