Minerals should be taken separately, and I don’t even take a multivitamin. I have separates for magnesium, potassium, and then one full spectrum mineral pill to allow for choice. I take them with food. Yeah, there are studies and what not about inhibition, but really I just don’t like getting vitamins from pills much.
Calcium plays well with magnesium, but not with iron. Calcium and iron should be taken at different meals.
Vitamin D enhances calcium absorption. Iron absorption can be hindered by the tannins in tea and wine, and can be enhanced by taking it with orange juice.