Yale Smart lock installed with Zwave, not Zwave+

  1. Is this correct (that everything should be + otherwise it may cause issues?

Provided your panel has a Z-Wave Plus radio, , you can use both Plus and Standard Z-wave devices together on the same network.

  1. how can I remove the device and re-pair it under Z-Wave+? I tried following the manufacturers removal instructions but it was unsuccessful.

If you need to remove and re-add a Z-Wave device, this is done from the panel. Locks should be within 6 feet of the panel when pairing, and for about 5 minutes after, to complete secure enrollment.