Ratchet, Field Medic // Ratchet, Rescue Racer | Preston, the Vanisher | Ajani's Welcome

(and one other card)

Cast
Ephemerate by paying ({W} magic symbol) , blinking
Ratchet, causing it to enter the battlefield as
Ratchet, Field Medic.
When
Ratchet, Field Medic enters the battlefield,
Preston and
Ajani's Welcome trigger.
Resolve the
Preston trigger, creating a token copy of
Ratchet, Field Medic that is a 0/1 Illusion.
Put the nontoken
Ratchet into your graveyard due to the legend rule.
Choose not to return
Ratchet to the command zone from your graveyard.
When the
Ratchet, Field Medic token enters the battlefield,
Ajani's Welcome triggers, causing you to gain 1 life.
The
Ratchet, Field Medic token triggers, causing you to convert it into
Ratchet, Rescue Racer, and return
Ratchet from your graveyard to the battlefield.
When
Ratchet, Field Medic enters the battlefield,
Preston and
Ajani's Welcome trigger.
Resolve the
Preston trigger, creating a token copy of
Ratchet, Field Medic that is a 0/1 Illusion.
Put the nontoken
Ratchet into your graveyard due to the legend rule.
Choose not to return
Ratchet to the command zone from your graveyard.
The
Ratchet, Rescue Racer token triggers, as well as
Ajani's Welcome.
Resolve the
Ratchet, Rescue Racer trigger, causing you to convert it into
Ratchet, Field Medic.
Put one of the
Ratchet, Field Medic tokens into your graveyard due to the legend rule.
Resolve the
Ajani's Welcome trigger, causing you to gain 1 life.
Repeat from step 7.