I think the most obvious candidates are Daniels, Walter, the Neomorph(s) and the Xenomorph. I don't know enough about the other roles/creatures to speculate beyond that. Now, knowing NECA doesn't do series with more than 3 figures, and that creatures sell better than humans (and androids), I assume series 1 would be 1 human and 2 creatures. Also, getting the most out of molds is important to their bottom line, so I expect there to be maybe multiple versions of some creatures if the line goes beyond 1 or 2 series.
Having said all that, my guess is:
S1 - Daniels, Neomorph, Xenomorph
S2 - Walter, variant of Neomorph or Xenomorph, As-yet Unseen creature
S3 - ?
I remember the flak NECA took when they didn't include Shaw in the first 2 series of Prometheus figs, so I imagine the lead character will get the Series 1 treatment this time around to avoid the same mistake in case the line doesn't take off.