I think you're overstating that article's conclusion about single-cell consciousness. It says that consciousness is an evolutionarily advantageous trait that *begins* with non-conscious activity at the single-cell level -- the point being that the development of consciousness provides advantages even before it reaches actual consciousness.
At least, that's what I think it says. That site is not particularly coherent.
Try this link:
http://brainmind.com/FetalBrainDevelopment.html
The researcher doesn't state when he thinks consciousness emerges, but he's pretty clear that the early brain activity is brain-stem related.