Yes, such a setup is possible. It is described further down in the article you linked:
https://wiki.archlinux.org/title/dm-crypt/Swap_encryption#With_suspend-to-disk_support
Yes. Setting up an encrypted swap partition that supports hibernation is described here:
https://wiki.archlinux.org/title/dm-crypt/Swap_encryption#Using_a_swap_partition
The simplest way may be to set up an encrypted swap file, so you don’t need to cut in a new partition.
https://wiki.archlinux.org/title/dm-crypt/Swap_encryption#Using_a_swap_file