That's it, Jay! Thank you!! A true miss for the "Analyze" button on the Service Editor window....
This issue still exists in 10.5 where it presents, in my case, as "ERROR 1369: Failed to create the service" in ArcMap.
The server log shows "Failed to create the service.: Invalid service definition. Cannot have "mixed" data stores with a feature service"
Removing images from the layout window does resolve the problem. The problem only occurs when "Feature Access" for the service is ticked as one of the Capabilities.
If you've removed everything from the map document except for data that all resides within the same database, I'd open a new arcmap session and drag the layers from map doc 'a' into new map doc 'b', then attempt to republish. Sometimes map documents hold onto old data references when they shouldn't.
I had a different problem. I built a mapping service in Portal to show how the app would look. Just wanted to show and get feed back from future users. I built it in a file DB so i could make changes easier. Well, when it came time to actually go into production with a feature service, I imported it into my SDE DB and changed the source on the Map document. That through my error. The advice to create a new map document with new data source was correct. Once I did that, all was well.