Which features of a wizard’s familiar, if any, are considered magical?

The find familiar spell has a duration of instantaneous, which implies that the familiar itself is not an ongoing magical effect. However, the spell provides a number of ongoing features that are definitely supernatural:

  • The familiar disappears when it drops to 0 HP.
  • The wizard can temporarily or permanently dismiss the familiar.
  • The wizard can communicate with the familiar telepathically.
  • The wizard can observe through the familiar’s eyes and ears.
  • The familiar can deliver touch spells on behalf of the wizard.

Which of these features are considered magical? For example, would any of them show up to a detect magic spell or be suppressed by an antimagic field? In addition, is my assumption above correct that the familiar itself is not considered magical?