Depends on how far your commute is. If it is only a few miles then you will probably be fine eating after you get to work. 10-15 miles and you may need something before you leave to keep you going at full steam ahead. More than 15 and definately both.
don't worry. give it a year or two and "recent research" will tell is it's ok to take vitamins again. haven't you noticed how a lot of research, especially nutritional that gets into popular press, cyclically contradicts itself?
At best they're just an expensive way to turn your urine yellow. Do you really believe supplements are a good thing? With anything you can probably pick and choose whatever you want, unless you think a little deeper and look at the broad consensus.
Whatever suits you, really.
I'd rather cycle on an empty stomach for 20-30 mins than on a full stomach. I shower and have brekkie at work (yoghurt and bran flakes) then a smoothie for lunch, and something a bit more substantial in the evening, if I can be bothered to make it.
But whatever you choose, don't skip breakfast completely.