Compensation capacitor(s) in instrumentation amplifier
Depends on the step-input response, the settling-time, you must have.

Also, if OA3 is not unity-gain-stable, that is a problem.

And if you use Meg Ohm resistors, then with typical opamp and PCB capacitances you can easily have 10KHz f3db points.
The added phaseshifts may convert that 10 usec/channel telemetry system  into an oscillator