The spatializer ends up with deinterleaved buffers as output signals, so how do you input the reverb signal from the spatializer to the global reverb as it does not seem to have an input but only a...

Please check the global reverb is handled here: https://github.com/superpoweredSDK/Low-Latency-Android-Audio-iOS-Audio-Engine/blob/master/SuperpoweredSpatializer/src/reverb.cpp