Here is an interview with a representative of the last known race, Agent Voxine, an enigmatic Mecharie devoted to the Dominion.
As always, the interview is fun but we don't learn much. Voxine is a Mecharie. But can we really speak of a woman?
In a discussion of Massively, Chad Moore (Lead Narrative) indicates that Mecharis are a robotic race but that there are physical differences between a male and a female Mechari. On the other hand, and strange as it may sound, they see themselves as gendered beings. Basically, they were emissaries. As organic beings respond better to sexual creatures, the Mechari was designed to incorporate this parameter.
If they resemble and consider themselves as sexual beings, can they reproduce for all that? Does the Mechari population continue to grow or are all Mecharis from the Eldan era? Does Protostar play a role in all of this? No answer for the moment. The Mecharis are masters of intelligence and they prefer to ask questions.
Their robotic components do not offer them any advantage in communication. They are not connected to each other and must use the same communication tools as the average individual. One could suspect a secret means of communication, allowing them to dialogue only among themselves, but it turns out that there is not currently.
It is justified to wonder the real role of Mecharis when we know their taste for observation and manipulation. Where is the real power of the Dominion? Are the Cassians puppets that the Mecharis manipulate? Not really. The Mecharis are entirely devoted to one mission, given by the Eldans: to preserve and develop the Dominion. They don't have a mission to take control, so they fulfill their mission exactly. No more. Forever. It doesn't matter who gives the orders.
Do not hesitate to read the sheet on Mecharis on the official website.