I believe natural healing does occur at the same rate for everyone. And at the moment I think that rate is somewhere around 1hp per hour.
As for healer NPCs, they do indeed exist - I own one myself. There were a few being auctioned off a while back, but I haven't seen any in a while. They were restricted at one point, although they may no longer be so.
"May the Grace of Ara go with you, and His Vengeance be wrought upon your enemies."