If the summoning of "Emissary of the Afterlife" is negated and it is destroyed by the effect of either "Horn of Heaven" or "Solemn Judgment", does it consider sent from hand or field to the graveyard?

Emissary of the Afterlife would not get it's effect, as it is never considered to have hit the field.

no it is not considered sent from the field to the graveyard because it never actually hits the field because horn of heaven or solemn judgement would negate his summon thus allowing you to summon again because emmisary of the afterlife was actually never summoned.

Actually, even if a Normal Summon is negated, you cannot make another one.