The ozonator causes a rise in pH not from the ozone itself but from the aeration it produces since the ozonator puts out mostly air into the spa. Having your TA be lower (closer to 50 ppm) and using 50 ppm Borates would help if you aren't doing that already.
As for chlorine before a soak, people usually start off with a low 1-2 ppm FC so that they don't notice much chlorine during their soak. It sounds like in your case the chlorine is getting to zero between soaks (mostly likely because of the large amount of ozone) so you're adding some chlorine beforehand to be on the safe side during the soak when presumably the ozone if off at least when jets are running. Technically you should add enough chlorine after each soak to still have a small residual for the next soak, but with your powerful ozonator that may need a lot of chlorine. Given the ozone on all the time, what you really have is more of an ozone spa where chlorine is mostly for during the soak. It's too bad you can't regulate the ozone on-time better.
If the ozonator is running all the time, then there is probably residual ozone in the bulk spa water and that would kill pathogens on surfaces, but as I noted it will also outgas and oxidize the spa cover faster. It hopefully shuts off when you use the spa; otherwise your breathing ozone is not good for you long-term. If your spa cover were not degrading and you were getting growth on spa surfaces, then I would have said that your ozonator had a de-gasser to prevent any ozone from getting into the bulk spa water, but that doesn't seem to be this situation.
As for ozone and bromine, they DO interact just as with chlorine, but ozone also produces more bromine from bromide. The net result when you have some bromide bank (either added initially from sodium bromide or created over time from spent bromine tabs) is that ozone produces bromine. However, it also uses the bromide bank up over time by converting some bromine to bromate (the same happens with chlorine where most becomes chloride but some becomes chlorate).