You normally build up the bromide bank by adding sodium bromide per instructions (0.5 ounces of sodium bromide per 100 gallons) which will get you to around 30 ppm bromide (equivalent to coming from 60 ppm bromine). The bromine you added with tabs will become bromide so will build up the bromide bank though probably not as much. If you just want to use tabs for now, you can, but if you want ozone to generate the bromine for you then you need to add some sodium bromide since it doesn't sound like you have enough.
Yes, the bromine level will drop over time, though with the ozonator it may settle down to a specific level (though with your low bromide bank it will probably get too low until you add more sodium bromide).
The odor you smell is bromine, not chlorine. And yes, that will reduce when the bromine level gets lower.
Yes, the TA should be around 50 ppm and also use 50 ppm Borates. This is for pH stability.