I mix calcium & vitamin D powder (KAL brand, easy-dissolve) in my mouthwash and still use topical fluoride.
Most sources tell me that calcium *and* phosphate are both needed to remineralize the teeth, topical vitamin D might help, and topical fluoride strengthens the enamel. Most remineralization products or fluoride mouthwashes at the store include some sort of phosphate or phosphorus. It's nearly impossible to find plain phosphorus or phosphates if you want to supplement or add to your own mouthwash. Still trying to figure that one out.
Do you use baking soda (sodium bicarbonate) at all to neutralize acids? My tap water is slightly acidic, so I use a pinch of baking soda to neutralize the acidity. pH strips work great btw. I have heard that baking soda is too abrasive on the teeth, but I think that is in crystal form. I think when totally dissolved it is non-abrasive.