So, I'm almost up to Forest of Spirits. Just have to do the Yeti part of Book 3 but a few things are happening.
1. My group is about to go to 6 players. Not my normal comfort zone, but I know I have to ramp up the AP's challenge in places to handle the group. Any suggestions besides MORE ninjas?
2. What should I do with Ameiko? I...the rest of the NPCs are fading to the background and I think it's time I focus on Ameiko and cut my losses with the cast. I can't focus on all of them, the current AP NPCs, AND the PCs. Too much headwork. I'm fine with ONE major NPC, but Ameiko's relationship to the rest of the group is weird. She brushed off the Bard (he came off as a touch creepy to her). She's been doing the leading from the rear for the adventure and frankly that doesn't sound like her.
3. The whole Scion thing needs to be cleared up. I need to add more Scions to the mix but I need a clear way to link them to the story. I think it's time the PC's step up as the heirs to free the kingdom of Minkai.
I see you on the four (five if you count Ulf) NPC's being a bit too much at times and it's hard to keep them all relevant. I try my best, but it doesn't always work, especially with Sandru and Koya.
As for Ameiko, her personality description and class (she's a brawler who can't brawl. Hrm.) don't mix well, IMO. I personally had An Event happen and rebuilt her into my homebrewn Swashbuckler class in both campaigns I am running and she is much more what I imagined her to be now.
As for your six players problem... add 50% opponents and you should be fine for this module. After the group reaches level 10, things will become much more complicated and you'll need to start to apply advanced templates, max hitpoints and combine encounters. Sorry to break that to you, but that's just the reality of running an AP with six player characters. I have to deal with just the same problem.
She's been doing the leading from the rear for the adventure and frankly that doesn't sound like her.
I think you should let her lead from the rear. If she actually leads for real, she's stealing the PCs spotlight.
An NPC can get into trouble so the PCs have to rescue her, or rescue the PCs after they've got into a hopeless sitation, or railroad the PCs away from actions the GM isn't prepared for, or follow the PCs around buffing them, or go off on her own having separate adventures, but if the NPC actually kicks down the door and defeats the bad guy, or comes up with clever strategies for the group to folow, the players are reduced to spectators.
Not sure I understand your third issue. Are you asking for a way to turn new players into scions? You can just have it be some kind of ritual performed with the seal for anyone whose proven themselves worthy. (This ritual involves taking the seal from the warding box - it works well if you can make this happen shortly before an attack by the Five Storms.)
3)how to add more scions
what! another bastard child?
the seal accepts them
Suishen becomes a real person
the new PC achieves some quest gaining a lost artifact or secret
perhaps they don't care about being royalty and just want to help out.
family quest from an other royal line (they want to undesecrate their families resting places)
a local hero joins up to free their people