While writing our dbt project we looked into more than 60 dbt projects to learn from prior work while developing Elementary, and have been inspired by different things in different places. You're right that we were inspired by a couple of techniques you used, one being that creative way to improve performance (though the 4 thread setting itself is the dbt recommendation in their docs). Another is using z-score for anomaly detection, which we saw in a number of related projects and it's widely used in the industry.
In terms of the lineage, you can see in the code that we mostly rely on query and access history that exist in Snowflake and Bigquery to parse the queries and learn about the connection between nodes in the graph. We use other python libraries like sqlfluff and sqllineage as low level parsers for some specific use cases which we extend and solve many things on top of them. Actually we're heavy open source users, depending on around 20 libraries, all MIT or Apache.