pH sensor buffering, gain, and offset with one inverting opamp
Well now that I've been made aware of the m vs M error I can see this simply won't be practical. While I can get resistors of appropriate values to make the above work for gain and offset, I probably can't be sure what source impedance I'll get from probe to probe, even from the same manufacturer so proper gain is likely to be big problem. Looks like it's back to two op-amps.

Still, I can use this without gain as a buffer then a second amp for the gain and still not need a negative rail.