Is readying action to use a magic item the same as readying action to cast spell?

What happens to a wildshaped druid that enters an Antimagic Field? …and Dispel Magic?

Wait, does this mean you can cast 2 leveled spells during the same turn?

If you use dimension door while falling, do you keep your momentum through the door?

How do extra attacks work with wildshape druid multiattacks/attacks?

Does a natural 20 mean an automatic success?