But I'm not 100% sure if the quests they give you count, as they are not technically a tenant of yours, they aren't assigned a Colony Deed in a room. They will even start asking your for quests as well. One thing to note, for the quests where they have you find and bring back a friend, those friends will stay at your colony. So if you noticed the quests tend to send you to the same places a lot, just put down a Flag to mark so you will be able to teleport to them faster. So for the ruins I'd just walk a little west to them, and for the Mine I simply put down a Flag, which act as teleport markers. I got lucky with my main base I made on the first planet of the game, just to the west of it was a small ruins of rubble, and this, along with the planet's Mine are the two places my tenants seem to send me. Sometimes these quests will have multiple steps to them, and the quests won't officially be completed until they give you a Reward Bag. These vary from asking you to find and escort a friend of theirs back to them, giving them specific items, giving or receiving items/gifts from the other tenants and merchants, and defeating enemies among others. These don't seem to be any different than the other randomized side missions any others NPCs will ask you to do. Once you get some tenants they will start asking you to do side missions for them.

The All Walks of Life achievement in Starbound (Windows) worth 24 points Attract 10 unique tenants.

How to make a flag in starbound