A lot of questions ! I will try to begin answers with my poor words but for the rules I'm not sure about the real transcription so I won't go in that side.
The Tri-Kazel's habitant have are good skill in leather, wood and stone craftwork. For the stone the peninsula littered with stones and engraved. Stone work is a traditionnal craft.- Besides the magiescience faction, what is the techlevel in the setting, is it around 1100 western Europe? or even earlier?
They are pretty good to construct stone-bridges et cities in stone. For exemple in Osta-Baille, capital of the Taol-Kaer country, a bridge a hundred meters connects two neighborhoods.
They have mills, too. And the magientist have made many improvements. However the population is globaly traditionnalist and novelty is generally recieve with prudence.
In fact, they are pretty good except in sailling : sea is dangerous so tri-kazellians are not sailors.
In the unist faith exist six orders with differents rules but there is a monastic one. In many ways there are many similarities with the practice of Catholicism as we could know, especially among the monks, precisely. There is one book of the range, the Tuath monastry, wich explain the life of monks and give a scenario inspired from the name of the rose.- The monastic order/s in the game, how much do they remind of the real monastic orders - do they follow the model of the poor christ - like the Fransican moncs or more along the lines of the Benedictines?
I also know that they see cold as cleansing of the soul/evil - but how do they practice it? Is it meditation in open rooms in the coldness of the night ore something else? And how much "divine magic" is common among them?
I think your campaign with monks could easilly be played in the Three Kigndoms.
The divine magic work with miracles but they are extremely rare. So most of the population considers them more as legends as facts.
Peninsula use its own currency : the daols. These are pieces in various metal alloys of triangular shape. You will see that the number three to one particular meaning in the traditions of the three kingdoms. Note : for the unist faith, it's the six.- How does the economic system work? Is it an abstract resource unit, or real coinage? And if yes to the latter, is it more then "copper to silver to gold"?
Now for the rules points I will let more fluent in english people than I respond you. And complete me. I hope you have at least provided some answers.
iz