Can I ride the Northwind Commuter 5 on gravel paths and bike paths?

Gravel paths: Yes. The Commuter 5 handles packed gravel paths fine. It isn't built for real mountain trails. For those, the Northwind Trail 2 is the better choice.

Bike paths: It depends on local rules. Some paths limit which e-bike classes are allowed. Check with whoever manages the path before you ride. Class 2 e-bikes are allowed in many places.