I know I'm veeeerrrry late to the party, but just started playing with this very useful app today. I too was wondering how to select various Fuji camera profiles with single click on my Akai LPD8. Here's what I did:
You will need to do this for EACH camera profile (a bit tedious, but it works well):
1. In Develop pane, edit photo to apply your desired camera profile.
2. In Presets panel (left column), Create Preset...select ONLY the "Treatment & Profile"
3. In MIDI2LR Develop Preset menu, select your newly created presets, one for each placeholder
4. In MIDI2LR app, assign/map desired button(s) to the preset(s) assigned in step 3 above.
Voila, now you can assign a different camera profile with each button press. I know it's a long time after-the-fact for your question, but hopefully this helps someone else...