Yes, players are allowed to humanize characters without a corporal form! They're also allowed to app the character in as a hunk of metal if they really want, because that's hilarious, but seeing as a human form would have to be gained as a power through bonus activity and is only available after one month in the game, humanization is the easiest route.

For the Ring-Spirit and other characters like him who possess others, giving them a human body is perfectly fine, without having to app them along with a host (as the host is likely an appable character on their own right). It would be their own body, and whether they're subjected to basic human needs like food and rest is up to the player.

All this information will be added to the faq too. Thanks for asking and let me know if anything needs further clarification!