Not quite. If I understand correctly from your links, the person selling the property then pays to continue living there. In the system I described, the person buying the property pays the seller an ongoing fee, and the seller continues to live there.

Really it can be whatever deal you work out. We don't really have laws preventing any sort of arrangement you might want to make.

>In the system I described, the person buying the property pays the seller an ongoing fee, and the seller continues to live there.

That's called a reverse mortgage in the US.

You can have arbitrary contractual arrangements (subject to local law), but the underlying property interests still matter, especially during disputes. I believe in the US a reverse mortgage typically means the mortgager (seller) retains legal title, with the mortgagee (buyer) taking a lien. But I believe an "en viager" is closer to the common law life estate, and in the context of reverse mortgage lookalikes would mean the mortgagee getting fee simple title with the mortgager retaining a life estate. A life estate arrangement was common, I believe, in the US before reverse mortgages became a popular product.