Question I am trying to setup 96 kHz operation via ADAT and it doesn't work; it just won't recognize a 96k signal from the ADAT input. Is that normal

Yes. 88.2 / 96 kHz (double rates) are not supported by the ADAT connections in the Reverb4000. If you need to work at double rate sample rates, you should use the AES or S/PDIF (coaxial) connections instead.