I've just been watching the talk on this at https://www.youtube.com/watch?v=yE3eMxYJDiE. GoshawkDB has a very similar design wrt the messaging and replication design. In fact, in some places, it appears that GoshawkDB's design is a little simpler.
There are obviously many differences too: for example GoshawkDB runs transactions on the client, GoshawkDB uses Paxos Synod instead of 2PC, and GoshawkDB clients only connect to one server so there are 2 extra hops, but that's a constant so from a scaling pov, it should behave the same.
One of the biggest differences is GoshawkDB uses Vector Clocks (that can grow and shrink) rather than loosely synchronized clocks.
This TAPIR work does look great - I had no idea that it was ongoing. I'll read through the paper too, but it's great that GoshawkDB has so many design ideas in common.