I've done a bit of reading on vitamins and antibiotics as i'm a distributor of a better quality vitamin/mineral combination.
I'm not a doctor but from what i've read, some vitamins (bs and k, etc.) can interfere with the antibiotic.
I would think you're iron and multivitamin should be taken earlier in the day - for energy. The calcium may help you relax and sleep - so take at night - especiallly if combined with magnesium.
If you can't take with breakfast but prefer to take with food to buffer your stomach why not take an hour or so before breakfast with a glass of milk or juice - then take your antibiotic with breakfast if you can take it with food.
As for bedtime - same thing. Take your antibiotic with food and then an hour or two later (or before) take your calcium.
***the ideal thing to do would be to consult with your doctor. He might have some better ideas as to timing the combining of your antibiotic with supplements.
Finally, if you're looking to restore lost nutrients be sure your vitamin is a good one. Take this test - put it in a glass of water and see what happens. Within 20 minutes it should disolve. If not, it's been bound too tightly and won't break down for your body's needs anyway.
Good luck. Feel better.