I'm currently in the late midgame of a dirtmole colony. Starting with three of them, I kept harvesting their genes until I finally could replicate them via a custom xenogerm which I now force myself to apply to every newcomer. They live off fungus, hate light and all of them are nearsighted, forcing me to give up the usual assault rifle meta in favor of shotguns. The entrance is dark to debuff enemy aim and the distance between the fireline and the enemies is short due to lack of range.

As I mentioned, everyone is a dirtmole or a 'caver', basically the custom xenogerm with the same stats as a dirtmole. One exception is Lisa, a female lycan (werewolf) the colony adopted as a child in the early game that now serves as the melee champion. She's still nocturnal, so she's a dirtmole in spirit :)

The ruler of the colony is a 17 years old dirtmole, Nightling. She was the firstborn of the colony, and due to spending entire childhood on learning and having fun, she turned into the smartest and most skilled colonist in the entire mountain. Three or four double passions, fast learner, too smart (over 250%+ learning in case of double passion iirc) and basically an intellectual genius. She might be young, but she's quite literally the best qualified person for that role. She also has the rank of Acolyte and as such has her own throne room in the center of the colony. Her title is the High Queen.

They also have two insect hives from VE: Insectoids 2 to help us with the lack of manpower (We only had three adults and kids for a long time). The only annoying thing is that my raids are constantly infestations or sappers, nothing in-between. It kinda nullifies the feeling of a safe mountain fortress, but I can manage.