There are only 4 EPA-approved disinfectants for spas: chlorine, bromine, Baquacil/biguanide/PHMB and Nature
2 with MPS. These are the only ones that pass the strict
DIS/TSS-12 requirements. Anything else you use would have a higher risk of pathogen growth. Enzymes do not kill pathogens -- they are just chemicals that can help to oxidize bather waste, but with an ozonator there shouldn't be any need for that. Minerals, specifically copper and silver ions, do not kill pathogens quickly and in the case of copper alone it doesn't kill fecal bacteria at all (see
this post for a comparison of kill times with chlorine vs. copper and silver).
If you are assuming that your wife is sensitive to chlorine because of exposure to concentrated bleach for the laundry or due to exposure in commercial/public pools (especially indoors), then those are not realistic comparisons to what you would experience in a properly managed residential spa. Most people target around 1-2 ppm Free Chlorine (FC) at the start of their soak so there is little or no smell and due to the Cyanuric Acid (CYA) in the water it's a lower active chlorine level than found in tap water. Does your wife have problems taking a shower or a bath such that you have activated carbon filters for both or for the whole house? If not, then she is not really sensitive to chlorine at low levels.
There are no government regulations requiring you to have a residential pool or spa be as sanitary as a commercial/public one. It is similar to having regulations on restaurants requiring hygiene, cleansed counter tops and equipment and proper refrigeration, but at home you can leave a chicken out all day on your counter and prepare vegetables in its spilled juices and potentially get sick from it -- the government doesn't regulate that. All the government regulates for residential pools and spa chemicals is that only registered pesticides that pass DIS/TSS-12 can make kill or disinfecting claims. So you will find all kinds of alternative treatments, but unless they additionally use one of the four EPA-approved systems I mentioned, then they cannot make disinfecting claims as that would violate FIFRA rules.
If your wife is truly sensitive to both bromine and chlorine, even chlorine at low levels, then your next best bet would be Nature
2 with MPS. Nature
2 supplies silver ions which when used with non-chlorine shock (MPS) at hot spa temperatures kills pathogens quickly. However, MPS is an irritant for some people but it is worth a try if you have to use a non-halogen approach.