A resistor in the force line (which is supposed to be broad and low resistance) seems odd and would just drop the voltage a little, although the feedback via the sense line would presumably correct that. But would you also need a resistor in the sense line as well.
This is true while the REF is trying to drive a tricky/heavy load, but falls apart if that's not the case. The problem is the chopper's charge switching will enter in tiny amounts on the inputs, and you don't want the REF's own error amp reacting resonantly with that to create instability. In many cases excessive direct capacitance going into the chopper's inputs can also mess with its chopping.
When the only draw for the REF is less than nA of current from an opamp, loading down the force line with resistance shouldn't be much of a problem because it's not like it has to provide current anyway, and the actual error is correct through the sense line. The poster child for the opposite case is of course an ADC which is swinging around Vref trying to charge capacitors and switching currents.
The primary critical thing for DC accuracy is the sense line can accurately sense the the voltage where you want the REF's output. So I would put a larger resistance on the force and a much smaller resistance on the sense.
Compromise of the OPA192 is much larger voltage noise (186: ~600nV, 192: ~1uV, 189: 100nV, all peak-peak) although there's trade-offs in all of them, depends which thing you want don't mind sacrificing
I've played with a 186 as well (was most attracted to 1uV offset and <10pA bias) and yeah it doesn't like capacitance at all, I found on its inputs or outputs. Just connecting it to a DVM I found it needed more loading to stabilise (practical workaround), I'm presuming cables and only 10M made it wobble.