Homebrew class for optional npc for party's wrath campaign

[Dawnseeker]

Coming online with this primarily because I have a bad habit of fearing overpowered shenanigans and preemptively nerfing to where I get encouraged to un-nerf by the players of my games. Fortunately everyone is having fun with the worlds I've built, the characters, music borrowed for backgrounds, etc. What I'd appreciate help with is giving concerns on where this could go awry with the goals in mind. I know one of my players had a significantly overpowered cleric, though

Overall context: 4 players anticipated for Wrath, semi-modifying the book versions to include some of owlcat's shenanigans (and I'm not averse to coming up with scenarios and maps to match), trying to balance things for 5-6 characters so they can bring an NPC or two to cover for their weaknesses. I already have permission from the group to include a DM-NPC since I demonstrated they only support the group and only suggest, not decide, and a heavier weighting of story decisions and player control/agency over power-play.

DM Experience: moderate, about 5 years of DM'ing off and on across skulls and shackles, kingmaker, and custom power-rangers-themed game. Only played in 2 campaigns, both kingmaker (different dms). decent knowledge of common races, feats, and skill uses, less so for extended/3rd party. Comfortable with homebrew/houserules to empower a character vision or negotiating to prevent overshadowing.

Party so far: elf ranger, elf wizard, half-elf bard (mute musician), and half-elf magus.
Party stats: Dice rolled, 1s re-rolled up to 3 times, get six iterations of 'hear the array and keep or drop+reroll', no party member rolled below 38 point buy equivalent.

NPCs being available: Seelah, Lann, Ember, later will likely include sosiel and regil (still have to check the 2nd/3rd books to see how it's handled there)

custom NPC in question: 20 point buy, obligatory low (4-7) dex because of jokes of my own clumsiness and a new challenge. Deity followed is Cihua Coatl

NPC goal: acceptable support, primary or secondary healer, possible 'off-tank', will be lighthearted and cheerful where able and likely start struggling with that effort during act/book 2 on the way to Drezen and be open to party influence to change who they are going into act/book 3.

Class: 3/4 BAB, charisma based spontaneous caster with full spell progression to level 7 (paladin/cleric spell lists), martial weapon heavy armor and shield proficiencies, 4+int skill progression.
lvl 1: 30 ft aura, +1 morale to saving throws, +2 at lvl 8, +3 at level 15. Wizard-esque familiar (if familiar dies, no spellcasting until quest/spell/process restores). Optional 'feature' to increase base scores over course of game to catch up to lowest player's roll equivalent. mythic will 'upgrade' familiar to an animal companion but spellcasting limitations still apply
lvl 2: lay on hands as paladin, +2 diplomacy/bluff to have others follow a plan, and ACP reduction ability (reduces ACP by 4 to maximum of -2 or armor's own, whichever is better)
lvl 4: Channel positive energy as hospitalier paladin
lvl 10: single wild shape available for minutes equal to level per day, weapons or weapon and shield merges with 2 claws and gains 1 bite attack, 40ft fly (clumsy), resistance 10 vs 1 chosen element (chosen at ability gain and not changeable), also counts as having teamwork feats for any that the familiar/companion may have
lvl 20: inspired by summoner, merges with familiar/companion to become a two-neck/headed dragon, gains additional standard action (limited to 1 set of attacks, may cast two spells with 2 standard actions, one for each head), requires an additional enemy positioned next to them to permit flanking (other requirements still apply for bonus), additional DR5/- with any other sources, all healing cast is maximized for the duration. duration is 10 rounds +2/mythic-point-expended. ability requires 1 week to recharge (unless plot demands otherwise).

As far as my own self assessment, I keep wobbling between overpowered because cleric spellcasting can be broken even if i intend to just focus on healing and support spells, and BAB/Spells are as good as the druid (who I've heard is able to be very broken easily). Then some days I see how few abilities there are and also see how it ends up being a Paladin+Druid hybrid class that can't do as much as either.

[Azothath]

okay - clerics are not broken or overpowered.
There is a post on "tiering" the classes by power. School specialist Wizards are on top.

There are several parts to a game. The story aspect. Managing the participants so things flow smoothly. Making sure things are Fair or seem to be (statistically the Game heavily favors the PCs). The ability of the PCs to modify the storyline. PCs do unexpected things sometimes and that's the fun of GMming. You have to roll with the punches.
At no point do the PCs ever compare to the power of a GM. Never. A GM is the world with unlimited resources, monsters, NPCs, etc. Ofcourse if a GM overdoes it, rocks fall from the sky, everybody dies, Game Over. No Fun.
GMs also have to avoid getting into competition with the players. It's pretty common.
GMs also need to run creatures as written. I've seen too many dumb monsters execute very clever strategies or do things out of character. Sure, a dog naturally hunts in a pack and can learn those tactics, in the game it takes a trick. So some things have costs.

As soon as you go Mythic things get crazy and the GM has to exert more control.

=== end GM Advice ===

IMO you should download the PFS Org Play documents and use that as a baseline. It has reviewed the material and banned the overpowered or unclear stuff. It is there in writing so everyone can use it. Archive of Nethys lists the legal items with icons.

For classes, you can go to the PF1 Build Guides on ZG and see what others think is really good and add strings or curtail them.

Using a 20pt ability buy is part of PFS1. 38pts is just over the top, so you know what you've got.

=== end Campaign Advice ===

IMO it's your Game not the classes that are overpowered.

If you want a lower powered NPC, use a PrC. Bloatmage villain, Mystic Theurge shop owner, Duelist, Golden Legionnaire, Magaambyan Arcanist ...

[Melkiador]

I do think you are too worried about “broken”, especially when involving mythic. There are only a couple things in the game that approach broken, like the master summoner archetype or leadership shenanigans. And when adding mythic even those begin to become less significant.

You are going to want the full cleric spell list in the party to remove all of the conditions.

It sounds like you are more interested in building a new character class than filling a role. And that can be fine. Though you need to keep in mind that you may be holding back as this build and not giving a true representation of how it would play in the hands of a PC