Agree with almost all points in this.
As long as all nodes interpret the custom json the same way and there are no malicious attacks, then everyone is happy.
Yep, but in the event of a malicious node or a break in consensus due to bad code, all other nodes can easily determine that the break has happened, as they all post a hash of their state every 10 minutes to check that they are in consensus.
Interesting. Thanks for the high-level overview. Sounds quite a bit like a side chain but using Steem for the checkpoints. Pretty cool. :)
Here is a good overview... I wish I would have seen this post as well. Glad so many of us are on the same page. https://steempeak.com/steem/@dlux-io/steem-alliance-proposals-or-dlux-side-chain-actions