1) First of all: Tag Team Arena has, unlike the classic arena, limited player numbers in all tiers above Bronze 1. It's very hard to climb up in Tag Team Arena.
2) Your teams are not build well, the champs don't synergize with each other.
A standard arena build with easy to obtain chamions could look like: High Khatun (lead postion, speed aura), Warmaiden, Spirithost, Starterchamp like Kael. This team would have a turnoder due the champion's speed from artifacts: High Khatun, Spirithost, Warmaiden, Kael.
They would ct in the following way: first move High Khatun A2, speedbuff. 2nd move Spirithost atkbuff. 3rd move Warmaiden, def debuff on all enemies. 4th move Kael, attack all enemies.
3) The named champs are easy to obtain, Spirithost and Warmaiden drop as loot in campaign (stage 4 and 9). Others can do the same job even better. You have a Tayrel. He can take Warmaiden's spot. He can do the same thing she can do (def debuff on all enemies), but he has even more nice moves if the fight takes longer. But basically all arena teams you build should follow the strategy above described: speedbuff, atk buff, def debuff, strong attack.
Teams that are slow and go second are much harder to build.