No, not Guild Guardians, Guild War Guardians, the group of troops that give boost to color, including: Aurai, Myzmer, Ogryn, Penquin, Peryton and Troglodyte.
Although, at this stage of game, it’s also possible they have nothing to do with Guild War at all, but a part of other mode entirely, like from 4.2 version.
Also, about AI defense silder topic, it’s not that simple like you think. I used to use it by giving each colors their rank, and slide the most useful color to the max. Turned out, that’s not how it work at all, and maxing a slider is not a recommended thing to do somehow. I still don’t know how to use it proproly to this day.
The slider seems to make AI’s behavior become more chaotic instead of more focus like intended, so they removed it.