We are currently working on an interactive DJ system in Unreal and looking for the optimal backend system to power load, seek, play, EQ and mixing of multi channel audio in realtime. Is this something that FMOD is designed to do/can handle in Unreal?
FMOD should be fine for your needs, we have had plenty of DJ apps use FMOD in the past. If you use the Core API which is the more low level / programmer approach there are a suite of effects including EQ that you could use.
If you use FMOD Studio with our Unreal integration, you can author content in the FMOD Studio tool and trigger things like snapshots to control mixing and effects like you would in a DAW (https://www.fmod.com/docs/2.02/studio/glossary.html#snapshot)
If you have more specific questions about formats and level of control let me know and I can point you in the right direction.