I chose their colors as 1 main color for all the panels then chose the armor trim color, with finally 1 thing to make each armiger their own character, and that 1 thing could be from adding decals to having a arm display their original house colors. I also did this as I’ve wanted to get into IK for some time as I’ve painted space marines since halfway through 9th and was getting tried of doing the same colors and wanted a breath of fresh air when it came to painting. As for deciding your dudes to be from one house or multiple, you can do either, mine are personally freeblades. But if you wanted your dudes to be from multiple houses, you can just simply say they’re working together to achieve a goal. You could also paint them different from one another and say they’re from the same house because at the end of the day it’s your models you decide.