Remarks on Eriahi
Some names attested in Etiuni can be found in later Armenian sources. Well known examples are the Welikuni/Welikuhi and Silukuni known in Armenian as Gelakuni and Cluk ( Ծղուկ) with regular w>g shift.
But instead Eriahi we find Shirak, which in most likelihood is a later Arsacid era term. Since Kapantsian theories has been proposed that Eriahi could be of Indo-Iranian origin based on their name similarity to Aria. However ancient DNA from Shirak region is not particularly supportive of this theory. We have dozens of ancient DNA from various sites in Shirak and none of them can be securely linked to Indo-Iranians. Eriahi seems to be a regular Etiuni tribe similar to other Etiuni tribes.
So was it's name lost? Maybe yes but most probably no. Eriahi's root is the Eria which could also have been pronounced as [eræ] according the Urartian orthographic rules. Or even as [aræ]. This would be quite close to the name of patriarch Ara. Many toponyms are linked to patriarch Ara. Aragats, the Ara mountain, Ara's field etc. However this theory has one important flaw. It's the geography. Most toponyms related to Ara are found in Araratian plain and only Aragats overlaps with Shirak. This can be solved if we imagine that they had larger settlement area or moved over time.