There is ample data showing varnishes with NaF and no calcium will deposit fluoride into enamel and dentin.  Fluoride does and will bind with the tooth in the presence of water and/or saliva, and doesn’t need an additional calcium source.
Yes, we do have Hydroxyapatite in our product which is a calcium phosphate crystal (the same that the tooth is made from).  It’s not needed unless the patient has dry mouth and no saliva.