I also don't have much euro experience, but as far as I understand most modules stick to about +/-5V range for bipolar signals, so that would be fine.
If inputs are used as a CV that modulates some parameter, it would generally be useful to have a CV attenuator for each input, to control the modulation depth. If you do that with a hardware pot, the user can scale down any voltage that exceeds the range without even realizing this limitation. Of course that kind of kills the idea of switching in software between in/out.
It should be ok to run this directly from eurorack power supply. It has an internal reference for the ADC and DAC, so it would be probably more accurate than the typical analog module even with less then perfect supplies. But the margin is not huge, if the supply voltages are wrongly adjusted.
Anyway I'm not sure if you can really mix/reconfigure the modes safely. From a quick look at the datasheet, in digital input mode the pins can take +6V max, so external voltage limiting would be needed in eurorack. For ADC input mode it seems the maximum voltage is 0.3V above/below the +/- analog rail. I would put a current limiting resistor and (schottky) diodes to +/-12V to protect the inputs. For example it is not unthinkable to connect a signal from a 15V modular system to a eurorack module.