The capacitor behind the pot should not be there - this would also avoid the problem of missing DC path for U1A.
Having one buffer OP for both filter sections is ok, there is only minimal interaction between the filters - even than its a question if it's better or worse to have worse filters at one OP.
Having the same value for R1/R4 would not change much with the gain, only a factor of 2/3.
Different input impedance is possible if the signal source is a one sided source - going to ground with the one side, while the other input sees the output impedance of the source. Anyway if needed adjustment would be better done with R2,R3. There is no really need for 1% precision für C1,C2 , 5% or 10% should be good enough. Currently R1/R4 are 50% off.
Having amplification and than attenuation again makes some sense, to get a higher signal level and thus less noise influence. The trouble could be too much gain behind the filters.