@ everyone, thanks for all the nice words and the feedback!

By playing
as if no-reloading I meant things like acting cautiously, using expendable items if they can turn the tables in a difficult encounter instead of reloading, trying to use reliable methods rather than save or else and reload until success, accepting less fortunate outcomes on skill checks etc. I really appreciate your concern and input, because it would be a shame to burn out on this great game.
You have already noticed that an unlisted benefit is that you still receive the School Bonuses of a regular wizard as a Thassalonian Specialist - that makes the class "worth it" imo. They are a super fun class to RP/play, but I think understandably unpopular. The extra spell slots are great in Kingmaker where spell slots are restricted (not so much in WotR where spell slots are 10 a penny)
Ouch, I'm kind of sorry to see Thassilonians fall off in WotR, as I liked imagining going through both games with one character.
On stats: personally, I might have gone with Elf, 8, 16, 10, 19, 12, 14. Your low Wisdom will come back and bite you every time someone casts a spell.
And this is even worse news lol. I guess I'll have to burn some feats on Will boosters then... Would 10 CON not be a bad idea with regard to the Fortitude save and early game survivability?
On the subject of Thassalonian penalties - losing access to necromancy and Evocation is fine, they are the lest useful schools imo - conjuration will make up for loss of evocation. The issue will be making most use of your bonus spells. I would recommend going full into Dispel and Banishment type spells since most Fey can be 1-shot in the main world using these and it's a unique and rare way to play. I played WotR a bit as a banishment specialist and it's great.
Sounds great, thanks!! I'll look into those spells.
Some other things - I don't consider a knock out a game ender, only a full death in which the MC is stone cold dead.
Noted, good to know.
would say this: think less about reloading/not reloading, more about your character, their build, your party synergies, the story, all those small details here and there. Considering one other aspect of Kingmaker, the story doesn't really start until chapters 3-4, stick to your playthrough, and give the game a chance when you will feel unfairly treated (and you will!).
Sound advice, thank you Antimatter! There's much to learn and to enjoy, and that's more important than a certain technical approach to playing the game...
Gerrit, Thassilonian Envy Mage (1)
Let me just post what Gerrit has accomplished so far (not that much lol). The prologue went fine. I don't think there's much to say about it. One casting of Mage Armor lasted Gerrit through it, which was nice. Tartuccio got knocked out in the library battle. Gerrit used his innate fiendish Frigid Touch once. It may well be the only time he'll use it in the game.
Harrim had to be intimidated into the party (diplomacy check failed, something I didn't know was possible in this case). Guards were saved from the fire. And the final battle went well with some slight buffs (Protective Ward, Bless) even though Amiri didn't show up to help out. Gerrit's most important contribution was a well-aimed Color Spray.
His conversation with Lady Aldori resulted in Valerie and Jaethal joining Gerrit along with the lovely Amiri on a trip to Oleg's Trading Post.
We overcame Kressle's bandits even while fatigued (took longer than normal) and earned our first level-up. Valerie took Weapon Focus Bastard Sword. I hope to build her into a solid tank that can still land hits, but I'm not sure if it's going to work. Amiri acquired the Lethal Stance ability. Jaethal got Cunning Initiative and learned Remove Fear. And Gerrit added Reduce Person and Snowball to his spell repertoire (PfAlignment, Shield, Stunning Barrier, Mage Armor, Color Spray, Grease, Hurricane Bow, True Strike, Expeditious Retreat).
Without Bokken's help but with traps, tar, and some castings of Grease we also won the bigger bandit fight. Oleg got knocked out by a bandit that managed to close in on him. The party rested and Gerrit got to know his companions a bit better. Jaethal turned out to be a particularly awful being, but Gerrit chose not to judge her for her past deeds. There was also some cautious flirting between him and Valerie.
The party was directed to the Ancient Tomb for a rendez-vous with Tartuccio. Some prebuffs (Mage Armor, Shield Protective Ward and Bless) were put in place before confronting Tartuccio. This can actually be a tough battle in my experience. However not having Harrim in the party and asking him to join helps. He occupies a melee thug that he's positioned right next to, so that our warriors can take on their archer and wizard while Gerrit casts Grease at their leader.
Valerie still took a beating, but no one got knocked out (except Harrim who wasn't in the party yet). I love Linzi, what I've seen from her, but Gerrit preferred some muscle in the party, which is why first Jaethal and now Harrim were chosen over her.
We successfully followed Tartuccio's trail to see him masquerade as a Kobold, before we moved on to Kressle's hideout in Thorn Ford. We first dispatched two bandits in the western part of the area without needing any buffs before we proceeded to face Kressle and her posse. Now I had played this battle before with my Ecclesistheurge and it was a miracle the party survived. Valerie was the last one standing with her HPs in the danger zone. I was worried this time we might not be so lucky. But we were. At least I think luck was involved. It was night time and it was raining, which meant that their two archers kept missing and the party could focus on the melee enemies who spent most of the time face down in the dirt thanks to Gerrit's Grease spells and Harrim's Bane spell. Grease + Spell Focus: Conjuration + Bane appears to be a pretty effective combo for the early game. Making sure the party's frontliners don't slip can be tricky though. The battle lasted a long time because we didn't get automatic (ranged) hits on the enemies on the ground, and we missed a lot. Grease lasts quite long though (already two minutes at level 2, and Gerrit had three castings). We threw some alchemical bombs to speed things up. I was happy we prevailed without taking much damage.
When we further explored the area we found the Stag Lord's wine, but we didn't get the opportunity to poison it, unlike in my Ecclesitheurge run. This is will make the fight with the Stag Lord much harder, I've read. Apparently there's a nature check that I failed. I just went with the unfavorable outcome, a good example of playing "as if no no-reloading". We traveled back to Oleg via the Abandonded Hut. We stocked up on camping supplies and we splurged on the bag of holding because we got encumbered all the time. On our way south we cleaned up the Boggard Hunting Grounds before we ran into a Technic League ambush. Unwilling to give up one of his companions, despite Jathal's volunteering, Gerrit ordered the party to fight. Bane and Grease, supplemented this time with Jaethal's Remove Fear, allowed us to dispatch the enemy. Honestly, I don't know how I'd handle these group fights without Grease (or a Druid's Entangle). She's supposed to be tanky, but the following screenshot shows how a single crit makes Valerie suffer against a warrior or two when they're not lying flat on the ground.
The party then passed a nature lore check to reveal the location of the Technic League camp. We traveled there, took on two guards without using up resources other than a Bless, and then the camp, much in the same way as the other groups we've fought so far. One thing Gerrit learned not to overestimate was the casting range of his Grease spells. One casting had him move forward catch more foes in the spell's AoE. Gerrit came somewhat close to a Technic League melee fighter who immediately aggo'd him, hit him, and might well have slain him if a second strike (of opportunity) had connected.
I'm also enjoying the alchemist bombs quite a lot. Here's Harrim disrupting an enemy mage with Alchemist's Fire.
We met Octavia and Regongar, spared Kalannah, and accepted Rengongar into the party. I hope Octavia went to Oleg's. I'm now going to look into Rengongar's class. I wonder if he could function as a decent tank with self-buffs, much like a Blade or Fighter/Mage in Baldur's Gate. We're sitting on 4431 XP, so level 3 looks to be somewhat close.