Scion is more magic'y, Saint is more fightery. Whatever floats your boat. End result is roughly the same, although saint is tiny bit less dependent on getting 20.
Blind run build is there mostly for exactly that. If you have no idea where the stuff is and don't want to look it up - it will likely be an easier run.
There is a bard valerie build. that'd work fine if you need a bard in your party.
jaethal cleric is pretty potent. After all, if your summons eat the damage, you don't need to heal it. And you would actually use all those pots the game drops on you that are usually sold for a few gold. Come endgame you will stock on mass heal scrolls and use those anyways.

I feel like the more I ask you the more I get unsure about my choice. I kinda wanted to play something similar to Red Mage from FF, I know it's cheesy. Aka Melee/Caster with some heal spells. I think the latter isn't possible outside from scrolls. Would Dex Scion be the best pick for that?

Also a question regarding the other caster:

I take it Sorcs are full on nuker and control?

What are Wizards then? Are they not good? I didn't see any builds here with them which is kinda sad since I usually like to play caster a lot and Sorcs give me a different vibe.

pretty much all arcane classes are different brands of good if you do it right.
mellee/divine is fine. Jaethal would have some heal spells and breath of life, When I talk about summons I mostly mean conversion of utility spells you don't need. And she does the whole chopping thing ok-ish.
I think what you really want from your cleric is kinda what Harrim does. If only old bugger didn't have merc-level stats...
Both dex scion and saint would be good enough at using scrolls. I guess Scion is a bit better at it, given his Cha.

I will definitely take your Jaethal Cleric build for my party. I like her a lot and I think I get how your build is supposed to work now. Thank you!

It's just that I'm still deciding on a caster build for my main character. I would honestly prefer a nuker that isn't Sorc. Hence why I looked at the Magus builds of yours since I couldn't find a Wizard build. But now I wonder if playing a pure ranged nuker first would be better than going hybrid melee/range in my case. Do you have any recommendations for a Wizard build "done right"?

https://www.gog.com/forum/pathfinder_kingmaker/ineffect_builds_for_you/post214
Although it does take mechanics knowledge to pull off glass cannon MC. Thing dies the moment something looks at it funny. And there are moments MC needs to fight on his own.

Dex scion is fine. If you are new to the game I'd go with scimitars instead of logswords and make sure to not miss the robe at armags. And it's "castery" enough. He does lean on melee pretty hard, though.
If you want a comfortable caster I'd go for something like that. https://www.gog.com/forum/pathfinder_kingmaker/ineffect_builds_for_you/post244
unless you really don't want sorc.

Ahhh I'm so sorry, I just realized that dex scion required to be Lawful-Good. I really wanted to be a Lawful-Evil character this time as I usually play the good Hero in rpgs so I kinda wanted to break that habit. I guess it means that the Sorc build you posted is out as well? I'm really sorry for the confusion.

It's all about the LG monk robes really. They are +5Dodge AC. LE monk robes are +1. You can go What about dragons? build as that one is a shifter by midgame and doesn't care about robes much.
Realistically, if you are not playing on hard/unfair it doesn't matter.

I think I will just play a LG Sorc build now since you went through all the trouble to help me. I will just play LE next time.
Please allow me one last question.
Out of the 2 sorc builds you mentioned: Dragon and the linked one, which one would you consider to be stronger?
I mean Dragon shift does sound nice but so is having a constant pet...

Sylvan sorc is stronger. Heightened stinking clouds and delay poison from cleric trivialize like half the game. And you get all the shiny toys like stormbolts as you don't have to concern yourself with melee and shifting.

And you get the pet for earlygame.

It's settled then. Thank you very much.

P.S.: I saw that the build isn't in the index on page 1 or I couldn't see it. I had trouble finding it again after I closed all the tabs but now I bookmarked it!

Is it correct that I can't select neither a Deity or a Domain at level 2 despite having the icons to select them? Also only Negative Channeling?

yep. She already has a god from inqisitor and Urgathoa only provides negative channel. On the bright side you get selective channel at 3 and can nuke stuff rather decently with it. Especially when you get +2d6 trinket.

Big big thanks. I'm sorry but I have to bore you with another question regarding the pet. Should I enable or disable any of its abilities? Power Attack/Fighting Defensively ?