Hi @matthias,
I’m partially connected to the team developing Holochain and will be a facilitator at the Amsterdam Hackathon.
I would not say that Holochain is the consensus of the Holo system, because Holochain does not use or talk all that much about consensus, certainly not the same way that traditional blockchains do. Holochain is eventually consistent and coherent, but this is done through sharing of actors actions through using a Distributed Hash Table (or DHT) which is what bittorrent is also built around.
The chain part comes from having each actor in a distributed application store the information that the person has authored locally first in an immutable chain so that it cannot be tampered with subsequently. States of chains are shared as hashes and conflicting information on DHTs will indicate bad actors.
The Holo part comes from modelling the systems around the concept of a holographic view. Every actor has a view of the whole, the more user viewpoints that can be integrated the better the granularity and clarity of the whole.
Hope to see any of you in Amsterdam 
(Will be good to see you again @jeremyboom8 
)