Advice on Schluter ditra install

A couple of days ago my girlfriend had tile installed in her master bathroom. It's a very small area (3'x5'), the subflooring is a soft concrete and the installer layed Schluter ditra on the subfloor and used Versabond thinset to set the small mesh back hexagonal tile. The next day we noticed the there was insufficient mortar coverage because we could see a lot of the orange ditra between the tiles and there were some low spots in the floor. The installer was a former neighbor and was doing the job as a favor, we didnt notice at the time but after talking with him, post install, it became apparent he may suffer from some sort of mental illness. Unfortunately, we think it's best he not come back to resolve the situation. My girlfriend and I are fairly capable DYIer's and I have installed a tile backsplash before so we will most likely make the necessary repairs, however we would like some advice on the best way to remedy the issues. I have attached some photos below I hope they are helpful. My questions are, is there any way to fill the gaps? Can we salvage any of the ceramic tiles? Do we have to tear it out and start over? There is toilet involved so if we do have to start over, is backerboard over the ditra a good option, or would there be issues with reinstalling the toilet? Can the ditra be salvaged after removing the mortar and tile? Lastly, if you think of anything I may have overlooked please feel free to elaborate. Thank you for your time.