The ADC has a digital input, you should look if it matches your output and then solder to it. Alternatively you could use the waveform coming from the output of your friend, use an opamp to create differential signals and the feed it to the same inputs like the micropohes are connected to. Be careful with the cable length though, could create a lot of noise.
Most likely SPA1687LR5H-1 since it is connected to the ADCs differential inputs and meets the specs and the dimensions.
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