ECU and Engine harness you got are no good for your swap. The throttle body system is the big reason. You need a throttle cable and that TB is electronic.
Sadly, you need quite a few parts to get this going.
You need a k20a (type r) or K20a2 (type s) engine harness. jdm will work fine. It's about a foot shorter than USDM harnesses but should be fine in a mini. You also need one of these throttle bodies and an adapter to make it connect to the existing intake manifold but it's not too expensive. (I suggest Karcepts)
You can get away with a PRC-O intergra type r ecu with very little mods.
Or a PRB but it will need an immobilizer bypass unit.
But K-Pro installed is way way better of a choice.
You need a universal conversion harness (I suggest Hybrid-Racing)
There are a few other little things (axles, shifitng, mounts) but this will get you started.