I'd like to discuss the theory of using tri-color fixing that only overlaps with your colorset on two fronts, and two-color that only overlaps on one side.
The first thing that stood out for me: you're running
Windswept Heath in a deck where there are no forests, and the only thing that counts as a plains is basic Plains (which is your most plentiful land anyway). Is it really worth running Heath instead of a plains to be able to pay a life to get one spontaneous library shuffle, a one-card deck thinning, and an extra card in your grave (for your one Delve card)?
The Temur Banner - your deck has exactly two sources of Green mana. In general, are mana rocks in this format so useful as acceleration that it's worth running a banner on two of your colors, for which you have little to no means of ever activating the 'refund' ability? What about if the banner only hits on one color you're using?
Those two sources of Green mana are
Thornwood Falls - another 'is it worth it' question - is it worth it to run those refuge lands to zero or near-zero support of the secondary color? Really, the vast majority of the time with this deck,
Thornwood Falls is just a bad Island (enters tapped, gives you a life, and really is only likely to be used for U).
I'm still trying to figure out if three color is really the best plan if you don't luck into bombs in a playable wedge. A lot of people will want to try to run 3 colors to rep their clan, but I strongly wonder if the best play would be to condense to a more manabase-reliable 2-opposing-color build and run all the best cards in those two colors of which there will be two representative clans. Headed into this weekend signed up for Abzan, but wondering if I should lock in on strict Abzan trio, or consider going WB AbzanMardu, or GB AbzanSultai.