The LTC6200 impedance at 10MHz is 100x higher than your C11=0.1uF
Also it adds overshoot with even light capacitance load.
If your transient loads are significant then OK add a series RC after the unity gain OP Amp but as I would expect , you wont have significant load current so the R ratio is adequate to feed many comparators.
get rid of Op Amp.
Also, what is the tolerance on your need for 0.8V because the tolerance on your Vcc will drive the error on this. 2%?? 5%??
Generally if you need a good reference we use LDO's or bandgap zeners but if your Vcc is stable within 0.8V tolerance spec, just the R ratio is fine.
RC= 6k//0.1uF results in a few hundred Hz LPF whether you have an Op Amp or not but at least no overshoot on turn on. (which may not matter)