Hey! Northeast here so I feel your pain.
Couple things to consider about APs:
1. If you want the hotel discounts, you only need 1 person to have the AP.
2. If you're looking for Express after 4 PM, each person would need the Premier pass, not the seasonal. That's the most expensive one so that adjusts your make/break points SIGNIFICANTLY.
3. If you want Express for your party, I'd suggest looking at Royal Pacific/Hard Rock/Portofino. Those include express for all guests of the hotel. It might be cheaper to do regular tickets + those hotels vs. Premier passes for express after 4 and SF.
4. I assume you know this but 4 PM in October you're gonna have issues with the studios closing soon for HHN, which makes your idea sub-optimal (in my opinion).
Like
@Brian G. said, when I get APs, I make sure I get them and last me 2 trips. Like go late October and buy the AP for that trip, then next year go in September/early October so I have the benefits and one less thing to buy.