The examples in the presentation were given with the WYE configuration? Is the isolation ADC also well-suited for the delta configuration?

Delta configuration can also be used. These are usually more common in “Indirect”, high current applications. In this configuration, the voltages are measured between 2 phases, and not in relation to the neutral, as is the case in the Wye configuration.

Usually the phase B is used as a reference. So there are only 2 iso ADCs needed. One used between Phase A and B and one between Phase C and B. There were 3, or even 4 isolated ADCs that were used in the WYE configuration, so it's a cost saving to consider if changing configuration is possible.