Like conventional (band) insulators, is conductivity in the charge-transfer insulator blocked by the Pauli exclusion principle?
There is definitely a difference. A band insulator can be understood simply as a result of filling the allowed states in the nearly free electron picture. To understand a charge-transfer insulator you must take into account the Coulomb interaction.
See this answer which is very related: Why is the distinction between Mott Insulators and Charge Transfer Insulators important?