One more thing. Do you see any problems with using a MAX410 with a Vref of 2.5V? I know it has to be within the common mode input voltage range (and it seems to be), but the data sheet is a bit confusing.
The other potential issue I see with this op amp is the very low Vs by specifications and how it limits the output V range, if at all relevant for this application, having in mind the high Vout required. This is more of a gut, undigested thought, so maybe it's not relevant but I'd appreciate your thoughts.