As a primary duty CAT-E ALO, I can tell you what I've heard at a very recent area meeting regarding promotions:
Three big things are required to get a DP to O-5:
1) Participation. Min points for a good year is 50, but they want to see more activity. I think 70-90 was thrown out there. As a minimum. More is better, and it is easy to find extra ways to contribute and earn those extra points. Just takes a little time and motivation.
2) PME. Has to be done or you are dead in the water.
3) Leadership positions. In the ALO world, you need to hold at least the Deputy LOD title to show you are doing/seeking leadership stuff. In a real squadron I'd say this amounts to being an ADO or maybe a DO (that's probably a stretch though).
If you meet these three requirements, you have a good chance of getting a DP, and for ALOs with a DP, promotion to O-5 has been 100%.
If you want to get promoted, the ALO/USAFA team (at least in my region) wants to help you get promoted. If you do #2 above, they will help with #1 and #3.
If you don't want to get promoted and just want to min run it, you can. I'm not sure where you heard sanctuary is different in the CAT E world, but I've talked with ALO leadership and a personnelist at AFRPC to confirm if or some reason I don't make 0-5, and I'm inside 2 years remaining, I can stay on, and I've been told this is the case by all. I'd need to see a reg that states CAT Es aren't the same as the rest of the AF regards to that if you've got it.
Hope that helps.