Here's one of the ways to set up multi-out for Addictive Drums 2 in Reason 12.5 of later.
1. Load Addictive Drums 2 into your project
2. Open the Addictive Drums 2 interface, go to the KIT page and click the Out arrow for every mixer channel you want to route.
3. Toggle to rack rear (shortcut: ⇥)
4. Click on "Optional Inputs & Outputs" at the bottom of the back of the Addictive Drums 2 module.
5. Right click on Optional Audio Output 3 and select "Route to new Mix Channel". This connects Optional Audio Output 3 & 4 to the inputs of a new mix channel.
6. Right click on Optional Audio Output 5 and select "Route to new Mix Channel", and repeat the process for all available outputs.
7. To set up the separate tracks for recording toggle to rack front (⇥) and activate "Rec source" on all the Mix Channels you've created. Then create an audio track for each Mix Channel and set the Audio Input on the audio track to Stereo Input and click Audio Input again and select the corresponding Mix Channel (for example "Addictive Drums 2 1 Kick (Mono)+Unspecified").
8. Make sure all the Audio tracks are record enabled and press the record button.