ADAU1701 Mono Signal, what is the best approach?

I  have a mono full range Audio signal, which I want to EQ with the ADAU1701.

Imput is 2V rms to use full range of ADC. 

The Amp after needs symmetrical inputs. 

So my first aproach was to use diff Input Buffer of any kind (above is only for Illustration, values not correct) like the above one.

So the above image would be a normal approach, SE in -> EQ Signal, Split it and switch phase on one signal.

But this leaves one ADC unused.... 

My question is, if I can improve the SNRR or THD by using both ADC Inputs. So I would buffer each Input Signal separately and use both ADCs:

So the above solution would use both ADC inputs with each 2V rms input.

After hat, I subtract (ADD) negative signal, EQ it and (if needed gain control it) afterwards output it again on two symmetrical lines. 

Or would the next approach even be better to use both inputs independently? 

This uses two channels independently and EQ both, positive and negative input signal exact the same way. And output both signals again independently.

Of course this would EQ the common mode errors with the signal... 

So my tip is, that the second approach is the best. Use both ADCs, mix signals together and EQ it and split it again afterwards (and scale it down to fit DAC output without clipping). 

What would be the best approach with the best performance?