I assume the question is related to your Linear Phase EQ thread over here?
If you want to measure the impulse response of an EQ to build up something like Waves Q-Clone for EQ plugins (not sure what you exactly plan…) I think the easiest solution from an end-users standpoint would be to make your plugin able to host a the EQ plugin you measure so that your plugin is the “host” and has access to all those information you don’t get from the host otherwise. But as I said I’m not completely sure if I really understood your idea 