Re: MOLA data.
Actually I thought of you when I posted this. If there is some way you can tell whether this is CO2 or water related then you could use it to test your theories. There seems a strong link between the fluid channels and the flat area. Perhaps the reflective index of ice is different.
Here is another photo that seems to get to the heart of the argument. The crater seems to have had some fluid ejecta and there are some faint channels on the cliff edge. It seems likely then that both fluids are the same. If it was possible to tell from this what the fluid was then it would imply many fluid channels are made from this fluid.
http://www.harmakhis.org/m2101602.jpg