The Wookiepedia lists the Z'Rakkon as a sentient species. At the same time, the page for The Endless Mercy is incomplete, as some of the names haven't had pages created for them yet. Maybe this is something that you may need to come back to at a later date.

As always, I'm willing to revisit subjects when more information becomes available.
As for the Z'Rakkon, I disagree with Wookieepedia on this, and when doing todays update (Sera Lemare), I realised that it's entirely possible we don't actually see any Z'Rakkon in this issue at all.
Doctor Lemare describes transforming her team of scientists into Z'Rakkon Hybrids, and that they tore each other apart, so she transformed herself into the Queen to control the Z'Rakkon hive. Whether this means that the creatures we do see are pure Z'Rakkon or the remaining Scientists become Hybrids, we're not told.
But what is clear is that the creatures we see do not show any signs of sentience, they never speak and appear to be bestial (to the point that when not under the control of a Queen they turn on one another), and all signs of sentience come from Sera Lemare who is a Z'Rakkon Hybrid Queen and directing the hive.
So perhaps the Queens are sentient? But I'm pretty sure the Z'Rakkon themselves are not.