Kent,
We are starting to implement PowerBI dashboards with our Epicor Cloud. We have found the easiest solution to be to pull data from Epicor by using REST connections that grab BAQs. The only downside is that it can be a bit of a clunky method with large datasets.
This is the best resource on REST that I have found: REST Overview Novel
In terms of physically connecting it to PowerBI it would be a “From Web” connection.