If calcium blocks magnesium absorbtion why are many supplements combining the two? Is it best to take them separately?

Also, with Vit. E. A supplement most likely is being sourced from safflower oil which is high in omega 6's being proinflammatory. How can someone take vit. E without increasing omega 6's?

You've got that the wrong way round. Magnesium is a natural calcium channel blocker. So it's magnesium that counterbalances the work of calcium.

Calcium tenses your muscle fibres and magnesium has the opposing effect and relaxes muscles.

Calcium excites brain neurones and Magnesium calms them.

So supplementing with calcium while being magnesium deficient means you have tense muscles (cramps) and are rather edgy. Ideally magnesium is best taken with food in small amounts through the day while calcium may not be required at all. Check your calcium food sources from one of the online calcium calculators, most people, particularly dairy consumers will NOT require calcium supplements and even if they do 600mg/daily should be the upper limit more than that generally does more harm than good.
Sources of Magnesium are generally deficient most adults consume less than half the official RDA and that is far too low.

Vitamin E Food sources