A:

Simply call AIL_set_room_type on the HDIGDRIVER. This will establish default reverb characteristics for the specified room type, which you can modify if you like with AIL_set_digital_master_reverb and AIL_set_digital_master_reverb_levels.

You will also need to use AIL_set_sample_reverb_levels to turn the wet effects level up for the 3D samples that should have reverb. The per-sample wet level defaults to 0.0, so if you're not hearing your selected room effects, this is probably why!