Granted, these examples we’re been talking about are sparse; yet I think they are valuable. They’re valuable because we can learn a few things from this historical information and these stories about what it means to be a Priestess of Isis.
There are five things that particularly jump out at me, and which, I believe they can give us with a foundation for exploring priest/esshood. I’m going to name them now…then we’ll come back and discuss each one in posts over the next few days.
First is the idea of SERVICE—whether that’s cleaning the temple or feeding the hungry or teaching or helping one person come alive to the Goddess.
Another is the idea that priestesses and priests of Isis have special KNOWLEDGE, including the knowledge that comes from experience.
Particularly from Dion Fortune’s example, we can see the importance of RITUAL ABILITY—ritual is communication; and if you’re going to be a priestess or priest of Isis, you need to be able to communicate with others, especially in this way.
In turn, ritual ability gives us a way to WORSHIP—certainly another central responsibility of a priestess or priest of Isis.
And finally, and perhaps most important, there is the need of personal SPIRITUAL DEVELOPMENT—which feeds your own soul, grows your spirit, and nourishes your ability to serve. If you are not doing this, you will not be able to do the others…at least not effectively or for very long.
Isiopolis 
Service, Knowledge, Ritual Ability, Worship, and Spiritual Development are indeed vital elements of any religious clergy. I feel too strict an adherence to Dogmatic tradition kills the fifth element, thus the re-evolution of religious paths.
It is as if the organic growing stops, thus a new seed sprouts when the time comes. I thank you for this concise layout of the Foundation of Priestess/Priesthood.