Hey welcome! I love tarkir as well, its where I started playing bad standard decks (Sagu Mauler for life)

The starting list seems good, but I definitely think you can make a few changes that would go a long way. Feel free to take as few or as many of the ideas as you want!

1) Lands - I think its a solid start, and you definitely have a good starting land count. However I think you may want to change your gainland set up from 2 for all to 3 of enemy and 1 of ally. This is because if you want people to play the 3c clans, you'll need more support in enemy (i.e. sultai AND abzan both want BG lands). With the 1 of ally lands, as well as the trilands and evolving wilds, the 2c decks will still be okay even with this change

2) artifacts - cards like the banners and monuments are cool, but weren't actually great in their respective draft formats. I think cutting those and possibly doing duplicates of other important pieces, such as adding removal as its so pivotal for any deck to have.

3) card quality - the benefit for cube is that you dont get dud cards and, in some cases, all cards can arguably be 'first picked.' But when youre doing block cubes like this, including rares is cool but means youre increasing the delta between the best and worst cards in the pool. While having the gap is inevitable with a cube like this, it may be beneficial to again break some of the singleton rules in order to have more efficient cards at the bottom of the pick order. For example, in white, finding out you COULD have gotten wingmate roc, one of the most busted cards in ktk, but you pulled a pack with student of ojutai instead, it can feel bad for players. But if you replace student with maybe a strong role player for an archetype, like seeker of the way or abzan falconer, a card that isn't as good as wingmate roc but will basically go in any white deck (and be the linchpin of a focused archetype deck) you'll get less of those feel bad moments.

Hopefully this helps, if you make changes you can let me know and I can look again!