The Founder's Effect, as your article points out, is only a problem if some of those in the founding generation have genetic abnormalities. In a genetically engineered population, this would not be the case. People who's genome has been designed from the ground up would be free of any such errors in their DNA, thus their genome would be extremely healthy and robust.

As for the term, breeding sized population, I see nothing wrong with it. Every species needs an adequate sized population in order to be viable. What would be the point of creating a new species just to have them go extinct? Being an entirely new species, it's not like they could breed with ours. I didn't mean it in any Orwellian sense.