After successful authentication you will see "Bioauth flow - authentication complete" and "We've obtained an auth ticket auth_ticket" in the log few seconds after biometric authentication. You will also you see "Starting consensus session on top of parent 0x..." in the log. It happens once a 10-15 minutes.
You can find it here if you did not delete the workspace - "$HOME/.local/share/humanode-peer/chains/humanode_testnet2/keystore".
It's a part of consensus. All blocks should be verified. You see this if somebody tries to propose an invalid block. It's not your fault.
Yes, they remain the same.
Yes, you can share an IP address as long as the peering ports are different.
We haven't implemented the final consensus yet, the main slowdown will likely be from it. We will launch another testnet when we're ready with this. Everything else does not contribute to the "blockchain speed" in the common sense of this term. However, we are EVM compatible chain, so we will likely be slower than DAG-based UTXO-only chains.
We currently distribute the node only via the desktop app. Before the main net we'll have that option.