The B12 I think is a life time commitment since as we age we don't absorb it well past about 50.

If you don't eat the omegas daily in your food (and now we have many "smart" foods to choose from), you need them also.
They are essential, like Vit C. We cannot live without them.
You may not need high doses anymore, but you cannot do without them in some way.

You may be able to lower your Bcomplex, with time.

If you eat well, you may be able to drop the cal/mag. Most people do not eat foods with good magnesium levels, so if you do that with your diet, a supplement will be necessary.

Many foods have calcium added. My Lactaid milk has 50% of the RDA in it/serving. There is OJ with calcium, breakfast cereals, etc.

If you are improving, then you are lucky. I don't think you will deteriorate unless you get another course of Cipro or its cousins. Now that you know you react to them, you can take the Vit E before any future treatments. I'd reserve those to situations where they are the LAST choice for you. You know they were intended from the start to be 3rd line drugs. Meaning, used when others fail or don't work, or because of allergies etc. The drug companies were aggressive in promoting them as first line to doctors, so they could make more money. That just exposed more people to the neuro side effects. The drug Floxin actually caused epileptic seizures which were permanent for some. There is a book written about it called Bitter Pills.