Earlier quoted context omitted.
It's "inspired" the dbt transformation part by using the same models and logic/part of code of generating them. We, for example, had a funny thing of computing metrics in 4 threads via multiple dbt models, and this is also done in elementary in a very similar way :) The lineage part is independent (re_data uses lineage from dbt), so I haven't looked into that much.
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 an…
Also, I think it's more than just following up re_data in a couple of places. Elementary's whole data monitoring part started much later than your Lineage part, and it seems to try to follow what re_data did there on the idea & implementation level. I'm sure the other 59 projects you mention were not dbt packages for data reliability (there were no other one in the dbt hub) which is what re_data is and now elementary also tries to copy this. (seeing our traction)
As mentioned, it's open-source. You can use our code. But if you are doing that, state that clearly in the LICENSE.