I would only ever give antibiotic when there is a real reason to so do. If there's been a lot of internal intervention, or if the ewe has mucky stuff / is not cleansing, or is pressing when there's no more afterbirth to come, for instance.
We do give lambs born indoors a squirt of Orojet or Spectam antibiotic as a preventative, but if I had just a few sheep I would expect to not need to do this. With a flock in the several hundreds, and highly unpredictable weather, events can overtake you, so we find the Oroject to be a worthwhile precaution.
Our ewes get a chelated mineral drench about 4-6 weeks before lambing. I would give a vitamin jab for a ewe who's had a rough lambing, yes.
Clostridial vaccinations must be given 2-6 weeks
before lambing in order to pass passive immunity to the lamb.
Anyone with dodgy feet gets them seen to after they've lambed and before they are turned out.
Our ewes get a fluke drench before lambing; we lamb earlier than we would expect worms to be active in these parts so do not worm the ewes until later on.
We lamb long before the flies are active.
As to routine footbaths, they may be necessary later in the year but at lambing time we have not usually got more than a few girls with sore feet. It is noticeable that a lot of the girls who were footsore before they lambed are fine afterwards - a friend of mine who has had a child tells me that's how she felt, too!