Hey Jonathon,
I'm currently pursuing that path with Devart dotConnect for PostgreSql, postGis, and EF6.
This is primarily for a project to replace some bad ETL juju.
I'm pretty sure I can get it to work out OK, but am still fairly early in the process.
Internally we tend to use ArcObjects quite a bit, but want to move to Pro and Runtime for future dev efforts.