Can I sync Airbnb's Non-refundable rate with Smoobu?

No, you can't. Smoobu synchronizes with your Airbnb standard rate. 

If you choose a Flexible or Moderate rate on Airbnb, you may "Add a Non-refundable rate". See example below. You'll be offering a 10% discount. Visit Airbnb.com for full Terms and Conditions.