Research-backed articles on cast iron seasoning
There is this research on Chinese equivalent of seasoning process called &quot;Kitchen God's Blessing&quot; [1].
They argue that the non-stick property of seasoning comes by iron oxide $(\ce{Fe3O4})$ nanoballs.
If they are correct then the oil or its polymers is not exactly what is causing the non-stick property but the those nanoballs on the surface. Their seasoning method is somewhat different however. It uses temperatures up to 450 °C.
Reference

Gao, C.; Yang, N.; Li, C.; Wang, X.; Yu, X.; Zhang, L.; Wei, Z. Seasoning Chinese Cooking Pans: The Nanoscience behind the Kitchen God’s Blessing. Nano Materials Science 2020. DOI: 10.1016/j.nanoms.2020.06.001.