I like #1
better. Artificial colonists that show no emotion and only need power to operate would be good but it may take from the difficulty of the game. Maybe we could make it so that the player has to build expensive mainframe centers that remotely control all of the robot colonists. In order to be able to have more robot colonists, you have to have more mainframes. This would make it expensive to have many robot colonists out at once.
Or, you could go another way with this:
New tech: Digital consciousness: Humans have reached the point where they can now download their consciousness into an artificial body and live forever.
Features of artificial colonists: no age limit. Entertainment still needed. food and water consumption rate reduced. 16 hour shift time due to their artificial body not needing sleep. These types of colonists will only be created when a colonist becomes old and is about to die. Then, that colonist can become an artificial colonist if the player has purchased the digital consciousness tech and has built the required structures.
New structure: Artificial body part factory: this factory can produce body parts that are part organic and part synthetic, and perfect mesh of the two. This building generates a resource called hosts because it builds synthetic bodies. Consumes food, water, plastic, oil, steel, gold, chips, alien artifacts, triantanium, and crystalline.
New structure: Consciousness downloading center: does exactly what it's named for, downloads the colonists very being and self awareness into the artificial brain of an artificial colonist. Consumes lots of power and alien artifacts. This building generates artificial colonists.
Culture around artificial colonists: These colonists are revered as the pioneers of advanced technology and are regarded as immortal. All colonists dream of being one some day. The only problem is that you have to grow old and die to become one.
This idea was sort of inspired by the dragoons in starcraft, where warriors would be downloaded into war machines called dragoons upon death. In sc II they are called immortals.
So that's my take, let me know if you like it.