i was just discussing this with Eero Technical Support and here is the latest on full IPv6 support with Eero. 

Full IPv6 functionality IS definitely planned for the near future, but no exact date is available; probably (but not definite) in next 2 months).

Internal network-wise, Eero provides IPv6 support, it just hasn't been enabled for external connectivity (internet) yet. 

I thought I would follow-up on this today since many Eero users have been requesting it here in the Eero Community.   I will pass on more information as I learn it.