My baby is EBF, and if I remember it right, your baby is EBF with complementary feeding, right? Currently, he's 5 months so we still follow the strict EBF recommendation. I never give him vitamins ever since he was 2 weeks old. He's at the pink of his health, active, rarely gets cold and cough. According to Breastfeeding Pinays, EBF babies do not need to be given vitamins unless there is a vitamin deficiency that has been proven through lab results. Too much synthetic vitamins can overwork your baby's liver.
If you really want to make sure that you get the right nutrients for your child, feed nutritious and natural foods but don't replace breastmilk as it's still the primary food for babies below 1 yrs old