My understanding is that the DME is looking for a specific output from the rear O2 sensors. Therefore you can't (1) eliminate them, nor (2) install them further back in the exhaust without a working catalytic converter in between. Re-programming the DME should resolve the CEL problem. A less expensive solution which might work (??) is the use of O2 simulators in place of the rear O2 sensors. The site
www.o2sensorsimulator.com provides an example of what's available for a relatively small amount of money and may be worth a try. Read the info at this site and decide for yourself.
Tom