I want to address your last point, as it made me very concerned. If your partner (or anyone else, such as myself) has celiac disease, that person cannot "get away with having minimal contact" in terms of contaminated surfaces, regardless of how long it has been since diagnosis. Celiac disease is an autoimmune disease that involves very specific damaging reactions in the small intestine to consumption of even minute quantities of gluten (20ppm is the current standard). That reaction, and intestinal damage, does not become less severe depending on how long since someone was diagnosed, or when they were diagnosed. It's like the old saw about being "almost pregnant"--either you have celiac and will have damaging intestinal reactions to minute quantities of gluten, or you don't. Some people may show different *symptoms* than others after gluten exposure, for sure; but the damage will happen, regardless of the outward symptoms. It's an actual autoimmune disease, not an allergic reaction.
There is no way that you would be able to safely make a gluten-free pizza on a stone that has been used for normal pizza. The residual flour from previous pizzas will contaminate the GF pizza for sure.
Now, all that being said, if you or your partner want to take that risk, that's your own personal choices to make, of course. But please, please don't be under the misconception that it's perfectly safe for your partner. It isn't.
If I may make a recommendation? I live with a non-celiac wife. What I do is I have a steel plate I use for baking (your partner could use his/her own baking stone) that can be removed from the oven. I then make my own GF pizza on that steel plate. My oven goes to 550, and I can get some pretty amazing pizzas from that steel plate--not true Neapolitan, but absolutely delicious, with browned/leopard-spotted crust, etc. I would highly recommend that you explore that route rather than bake a GF pizza on the same stone as your normal pizzas.