I am a bit confused… This thread seems to say that we cannot simulate mixed sources models (because the volume sources will have free orientation) while this thread Simulate activity in subcortical structures using MNE python? seems to say it is possible, although it is a bit short in details.
So, just to be clear, is it possible to simulate a mixed source model and if so what combination of loose, fixed, and pick_ori allows to estimate mixed sources that are compatible with the simulation routines?
If it is not possible as @larsoner seems to say, I guess I would just like to put a thumb up for this feature request 