Step 3... You expect humanity WOULDN'T be hostile??? It tear the fabric of society across the world. A transmogrification of half the species would be baptized in blood and tears. Globally the response would not be uniform. 'Gentle and compassionate' politically correct countries might meet the change with quarantine, detention and displacement / prison ghettos. Elsewhere, genocide would be the first order as soon as people got organized.
John Q Citizen of the global village would flip shit. They'd think it was an attack, an act of god to punish them, a disease, alien invasion. The day of the change there would be an almost global frenzy of rioting and fear, with whole regions collapsing into states without the rule of law and roaming mobs running on a fever of fear and hatred.
It's unlikely 3.x billion furries would be killed, but being immediately rejected from the human state and unfamiliar with their new bodies would leave them vulnerable and initially isolated, panicked and confused in the face of their former species anger and access to society they mean to defend.
After all the madness and death, in time, a tolerance might grow, but if they cannot breed and procreate with humans, they could simply be considered a harmful mutation nobody wants. In keeping with that thought, if the metahumans/transhumans/mutants are capable of bearing mixed children, males would likely be seen as a sexual threat, at best, by our collective animal mind. You probably noticed our species is competitive and wants to rule everything possible in the natural world and thought.
Make an interesting book maybe.