Emet-Selch's last ability checks your graveyard at the moment it would trigger to see if you have fourteen or more cards in your graveyard. If you don't, the ability won't trigger at all. If it does trigger, the ability will check again as it tries to resolve. If you don't have fourteen or more cards in your graveyard at that time, the ability won't resolve and none of its effects will happen.

You pay all costs and follow all timing rules for cards played with the permission granted by Hades, Sorcerer of Eld's second ability.

If you discard a card while you control Hades, Sorcerer of Eld, abilities that function when a card is discarded (such as madness) still work, even though that card never reaches your graveyard. In addition, spells or abilities that check the characteristics of a discarded card (such as connive) can find that card in exile.

If a Hades, Sorcerer of Eld you control is destroyed by a spell you own, Hades will be exiled and then the spell will be put into your graveyard. Conversely, if a Hades you control is dealt lethal damage by a spell you own, the spell will be exiled, and then Hades will be exiled as well.

While you control Hades, Sorcerer of Eld, abilities that trigger whenever a permanent you own is put into your graveyard from the battlefield (for example, "When this creature dies . . .") won't trigger.