Kaya, Intangible Slayer

Kaya's last ability checks to see whether the permanent was an Aura when it last existed on the battlefield, not whether it is an Aura card in exile. For example, if an enchantment creature with the bestow ability (an ability that allows a creature card to be cast as an Aura instead) is an Aura and the target of Kaya's last ability, the ability will not create a copy of it.

If the copied creature is a token, the new token that's created copies the original characteristics of that token as stated by the effect that created that token, with the exceptions noted above.

For the middle loyalty ability, each opponent in turn order chooses whether or not to scry. Those who do (likely all of them) look at the top card of their library at the same time, then they decide in turn order where their card goes. Each opponent will know the choices of previous players in turn order before making their own choices.