At the moment, Blocs Wave doesn't support AU (audio units), so you won't be able to record into Blocs Wave using AU instruments or apps. However Blocs Wave does receive inter-app audio.
This means you'll have to select an input from the Apps section in Audiobus
Please also make sure you have enabled Local network in your device settings for Audiobus, Blocs Wave and the app you are recording.
In Audiobus, make sure you have enabled Multiroute audio.
In Audiobus's sync settings, make sure you have enabled Inter-app Audio Sync, if you want to sync play/stop using Audiobus's transport controls.