I got some procs that I want to always run in my game such as a healing proc that basically adds hit points then sleeps for a certain amount of time and loops again.
Should I just run the proc after a character is created and after characters are loaded, or is there a better way to do it?

Your way would work fine: just kick off the proc for each new mob that's created. One alternative would be to maintain a list of mobs that can heal, and cycle through it every so often, instead of handling it separately for each individual mob. That might offer some minor advantage in CPU usage, but probably not enough to make any kind of difference. Your idea sounds good.