So I just recently tried a team that had 2 of the same color along with what I thought would be decent synergy against a team in war that was leveled significantly higher than me, LittleJohn/Kiril (both emblemed nicely)/Aegir/Domitia and Vivica all maxed…I beat them with the first flag! #Progress
My team was Mitsuko/Isarnia/Boldtusk/Joon/Caedmon, none maxed, but BT/Caed is on final tier and the other 3 are all on 3rd ascension
So I notice that with two of the same color the tile damage is higher as well as the mana generated a tad faster than normal, mitsuko held back their mana which allowed Isarnia (slow mana) time to go off which I love to fire her right after BT, and Joon/Caedmon were perfect snipers to kill. Aegir was their tank.
Definitely not the best combos of all, but not bad for my first go round at not having a rainbow team and using them in AW